In C++, la stringa è un oggetto di std::stringa classe che rappresenta sequenza di caratteri. Possiamo eseguire molte operazioni su stringhe come concatenazione, confronto, conversione ecc.
Esempio di stringa C++
Vediamo il semplice esempio di stringa C++.
#include using namespace std; int main( ) { string s1 = 'Hello'; char ch[] = { 'C', '+', '+'}; string s2 = string(ch); cout<<s1<<endl; cout<<s2<<endl; } < pre> <p>Output:</p> <pre> Hello C++ </pre> <hr> <h2>C++ String Compare Example</h2> <p>Let's see the simple example of string comparison using strcmp() function.</p> <pre> #include #include using namespace std; int main () { char key[] = 'mango'; char buffer[50]; do { cout<>buffer; } while (strcmp (key,buffer) != 0); cout<<'answer is correct!!'<<endl; return 0; } < pre> <p>Output:</p> <pre> What is my favourite fruit? apple What is my favourite fruit? banana What is my favourite fruit? mango Answer is correct!! </pre> <hr> <h2>C++ String Concat Example</h2> <p>Let's see the simple example of string concatenation using strcat() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); cout << 'Enter the buffer string: '; cin.getline(buffer, 25); strcat(key, buffer); cout << 'Key = ' << key << endl; cout << 'Buffer = ' << buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let's see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;></pre></'answer></pre></s1<<endl;> Esempio di confronto di stringhe C++
Vediamo il semplice esempio di confronto tra stringhe utilizzando la funzione strcmp().
#include #include using namespace std; int main () { char key[] = 'mango'; char buffer[50]; do { cout<>buffer; } while (strcmp (key,buffer) != 0); cout<<\'answer is correct!!\'<<endl; return 0; } < pre> <p>Output:</p> <pre> What is my favourite fruit? apple What is my favourite fruit? banana What is my favourite fruit? mango Answer is correct!! </pre> <hr> <h2>C++ String Concat Example</h2> <p>Let's see the simple example of string concatenation using strcat() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); cout << 'Enter the buffer string: '; cin.getline(buffer, 25); strcat(key, buffer); cout << 'Key = ' << key << endl; cout << 'Buffer = ' << buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let's see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;></pre></\'answer> Esempio di concatenazione di stringhe C++
Vediamo il semplice esempio di concatenazione di stringhe utilizzando la funzione strcat().
coppia C++
#include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); cout << 'Enter the buffer string: '; cin.getline(buffer, 25); strcat(key, buffer); cout << 'Key = ' << key << endl; cout << 'Buffer = ' << buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let's see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;> Esempio di copia di stringhe C++
Vediamo il semplice esempio di copiare la stringa utilizzando la funzione strcpy().
#include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;> Esempio di lunghezza di stringa C++
Vediamo il semplice esempio di come trovare la lunghezza della stringa utilizzando la funzione strlen().
#include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;> Funzioni di stringa C++
| Funzione | Descrizione |
|---|---|
| int compare(const string& str) | Viene utilizzato per confrontare due oggetti stringa. |
| lunghezza intera() | Viene utilizzato per trovare la lunghezza della stringa. |
| void swap(string&str) | Viene utilizzato per scambiare i valori di due oggetti stringa. |
| stringa substr(int pos,int n) | Crea un nuovo oggetto stringa di n caratteri. |
| dimensione intera() | Restituisce la lunghezza della stringa in termini di byte. |
| ridimensionamento vuoto(int n) | Viene utilizzato per ridimensionare la lunghezza della stringa fino a n caratteri. |
| stringa&sostituisci(int pos,int len,string&str) | Sostituisce la parte della stringa che inizia nella posizione del carattere pos e si estende su caratteri len. |
| stringa&append(const stringa&str) | Aggiunge nuovi caratteri alla fine di un altro oggetto stringa. |
| carattere& at(int pos) | Viene utilizzato per accedere a un singolo carattere nella posizione specificata pos. |
| int trova(string& str,int pos,int n) | Viene utilizzato per trovare la stringa specificata nel parametro. |
| int trova_primo_di(string& str,int pos,int n) | Viene utilizzato per trovare la prima occorrenza della sequenza specificata. |
| int find_first_not_of(string& str,int pos,int n ) | Viene utilizzato per cercare nella stringa il primo carattere che non corrisponde a nessuno dei caratteri specificati nella stringa. |
| int find_last_of(string& str,int pos,int n) | Viene utilizzato per cercare nella stringa l'ultimo carattere della sequenza specificata. |
| int find_last_not_of(string& str,int pos) | Cerca l'ultimo carattere che non corrisponde alla sequenza specificata. |
| stringa&inserisci() | Inserisce un nuovo carattere prima del carattere indicato dalla posizione pos. |
| int dimensione_massima() | Trova la lunghezza massima della stringa. |
| void push_back(char ch) | Aggiunge un nuovo carattere ch alla fine della stringa. |
| vuoto pop_back() | Rimuove l'ultimo carattere della stringa. |
| stringa&assegna() | Assegna un nuovo valore alla stringa. |
| int copia(string&str) | Copia il contenuto di una stringa in un'altra. |
| carattere&indietro() | Restituisce il riferimento dell'ultimo carattere. |
| Inizio dell'iteratore() | Restituisce il riferimento del primo carattere. |
| capacità intera() | Restituisce lo spazio allocato per la stringa. |
| const_iterator cbegin() | Punta al primo elemento della stringa. |
| const_iterator cend() | Punta all'ultimo elemento della stringa. |
| vuoto chiaro() | Rimuove tutti gli elementi dalla stringa. |
| const_reverse_iterator crbegin() | Punta all'ultimo carattere della stringa. |
| const_char*dati() | Copia i caratteri della stringa in un array. |
| bool vuoto() | Controlla se la stringa è vuota o meno. |
| stringa e cancella() | Rimuove i caratteri come specificato. |
| carattere&front() | Restituisce un riferimento al primo carattere. |
| operatore stringa&�+=() | Aggiunge un nuovo carattere alla fine della stringa. |
| operatore stringa&=() | Assegna un nuovo valore alla stringa. |
| operatore carattere[](pos) | Recupera un carattere nella posizione specificata pos. |
| intrfind() | Cerca l'ultima occorrenza della stringa. |
| fine dell'iteratore() | Fa riferimento all'ultimo carattere della stringa. |
| reverse_iteratorrend() | Punta al primo carattere della stringa. |
| vuoto restringere_per_adattare() | Riduce la capacità e la rende uguale alla dimensione della corda. |
| char* c_str() | Restituisce il puntatore a un array che contiene una sequenza di caratteri terminata con null. |
| const_reverse_iterator crend() | Fa riferimento al primo carattere della stringa. |
| reverse_iterator rbegin() | Fa riferimento all'ultimo carattere della stringa. |
| riserva vuota (lente inr) | Richiede una modifica della capacità. |
| allocator_type get_allocator(); | Restituisce l'oggetto allocato associato alla stringa. |