C++ std::string::erase用法及代碼示例

該函數將刪除一部分字符串內容，從而縮短字符串的長度。受影響的字符取決於所使用的成員函數版本：
返回值：erase()返回* this。

1. 語法1：擦除字符串中的所有字符

   string& string::erase ()

   // CPP code to illustrate 
   // erase() function 
     
   #include <iostream> 
   #include <string> 
   using namespace std; 
     
   // Function to demo erase() 
   void eraseDemo(string str) 
   { 
       // Deletes all characters 
       str.erase(); 
     
       cout << "After erase():"; 
       cout << str; 
   } 
     
   // Driver code 
   int main() 
   { 
       string str("Hello World!"); 
     
       cout << "Before erase():"; 
       cout << str << endl; 
       eraseDemo(str); 
     
       return 0; 
   }

   輸出：

   Before erase():Hello World!
   After erase():
   

2. 語法2：刪除位置“ pos”之後的所有字符

   string& string::erase (size_type pos)
   - Throw out_of_range if idx > size().

   // CPP code to illustrate working of 
   // erase(idx) 
     
   #include <iostream> 
   #include <string> 
   using namespace std; 
     
   // Function to demo erase 
   void eraseDemo(string str) 
   { 
       // Deletes all characters except first one 
       str.erase(1); 
     
       cout << "After erase(idx):"; 
       cout << str; 
   } 
     
   // Driver code 
   int main() 
   { 
       string str("Hello World!"); 
     
       cout << "Before erase(idx):"; 
       cout << str << endl; 
       eraseDemo(str); 
     
       return 0; 
   }

   輸出：

   
   

   Before erase(idx):Hello World!
   After erase(idx):H
   

3. 語法3：從索引idx開始最多擦除* this的len個字符。

   string& string::erase (size_type idx, size_type len )
   - If len is missing, all remaining characters are removed.
   - Throw out_of_range if idx > size().
   

   // CPP code to illustrate 
   // erase(size_type idx, size_type len ) 
   #include <iostream> 
   #include <string> 
   using namespace std; 
     
   // Function to demo erase 
   void eraseDemo(string str) 
   { 
       // Deletes 4 characters from index number 1 
       str.erase(1, 4); 
     
       cout << "After erase:"; 
       cout << str; 
   } 
     
   // Driver code 
   int main() 
   { 
       string str("Hello World!"); 
     
       cout << "Before erase:"; 
       cout << str << endl; 
       eraseDemo(str); 
     
       return 0; 
   }

   輸出：

   Before erase:Hello World!
   After erase:H World!
   

4. 語法4：刪除迭代器位置pos處的單個字符。

   string& string::erase (iterator pos)
   - Return the first character after the last character removed
   - If no such character is remaining then, returns 
     string::end() i.e. position after the last character.
   

   // CPP code to illustrate 
   // erase(iterator pos) 
     
   #include <iostream> 
   #include <string> 
   using namespace std; 
     
   // Function to demo erase 
   void eraseDemo(string str) 
   { 
       // Deletes character at position 4 
       str.erase(str.begin() + 4); 
     
       cout << "After erase:"; 
       cout << str; 
   } 
     
   // Driver code 
   int main() 
   { 
       string str("Hello World!"); 
     
       cout << "Before erase:"; 
       cout << str << endl; 
       eraseDemo(str); 
     
       return 0; 
   }

   輸出：

   Before erase:Hello World!
   After erase:Hell World!
   

5. 語法5：刪除迭代器位置pos處的單個字符。

   string& string::erase (iterator beg, iterator end )
   - Erases all characters of the range [ beg, end)
   - Returns end i.e. the first character after the
     last character removed.
   - If no such character is remaining then, returns 
     string::end() i.e. position after the last character
   

   // CPP code to illustrate 
   // erase(iterator pos, iterator end) 
     
   #include <iostream> 
   #include <string> 
   using namespace std; 
     
   // Function to demo erase 
   void eraseDemo(string str) 
   { 
       // Deletes all characters between 0th index and 
       // str.end() - 6 
       str.erase(str.begin() + 0, str.end() - 6); 
     
       cout << "After erase:"; 
       cout << str; 
   } 
     
   // Driver code 
   int main() 
   { 
       string str("Hello World!"); 
     
       cout << "Before erase:"; 
       cout << str << endl; 
       eraseDemo(str); 
     
       return 0; 
   }

   輸出：

   Before erase:Hello World!
   After erase:World!