C++ std::string::resize()用法及代码示例

resize()使您可以更改字符数。这是我们将描述C++中std::string::resize()支持的两种语法
返回值：没有

语法1：将* this的字符数调整为num。

void string::resize (size_type num)
num:New string length, expressed in number of characters.
Errors:
Throws length_error if num is equal to string::npos.
Throws length_error if the resulting size exceeds the maximum number of
characters(max_size()).

注意：如果num> size()，则其余字符由“ \ 0”初始化。

// CPP code for resize (size_type num) 
  
#include <iostream> 
#include <string> 
using namespace std; 
   
// Function to demonstrate insert 
void resizeDemo(string str) 
{ 
   
    // Resizes str to a string with 
    // 5 initial characters only  
    str.resize(5); 
    cout << "Using resize:"; 
    cout << str; 
} 
  
// Driver code 
int main() 
{ 
    string str("GeeksforGeeks "); 
   
    cout << "Original String:" << str << endl; 
    resizeDemo(str); 
   
    return 0; 
}

输出：

Original String:GeeksforGeeks 
Using resize:Geeks

语法2：使用字符填充size()和num之间的差异。

void string::resize (size_type num, char c )
num:is the new string length, expressed in number of characters.
c:is the character needed to fill the new character space.
If num > size(): character c is used to fill space.
If num < size(): String is simply resized to num number of characters.
Errors:
Throws length_error if num is equal to string::npos.
Throws length_error if the resulting size exceeds the maximum number of
characters(max_size()).

// CPP code for resize (size_type num, char c ) 
  
#include <iostream> 
#include <string> 
using namespace std; 
   
// Function to demonstrate insert 
void resizeDemo(string str) 
{ 
    cout << "Using resize:" << endl; 
    cout << "If num > size():"; 
      
    // Resizes str to character length of 
    // 15 and fill the space with '$' 
    str.resize(15, '$'); 
    cout << str << endl; 
    cout << "If num < size():"; 
      
    // Resizes str to a string with 
    // 5 initial characters only  
    str.resize(5, '$'); 
    cout << str; 
} 
  
// Driver code 
int main() 
{ 
    string str("GeeksforGeeks"); 
   
    cout << "Original String:" << str << endl; 
    resizeDemo(str); 
   
    return 0; 
}

输出：

Original String:GeeksforGeeks
Using resize:
If num > size():GeeksforGeeks$$
If num < size():Geeks

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注：本文由纯净天空筛选整理自 std::string::resize() in C++。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。