C++ vector shrink_to_fit()用法及代码示例

vector::shrink_to_fit()是C++ STL中的内置函数，可减小容器的容量以适应其大小，并破坏超出该容量的所有元素。

用法:

vector_name.shrink_to_fit()

参数：该函数不接受任何参数。

返回值：该函数不返回任何内容。

以下示例程序旨在说明上述函数：

// C++ program to illustrate 
// the vector::shrink_to_fit()  
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
  
    // Initialized vector 
    vector<int> v(10); 
  
    for (int i = 0; i < 10; i++) 
        v[i] = i; 
  
    // Initial vector 
    cout << "Vector size initially: " << v.size(); 
  
    cout << "\nVector elements are: "; 
    for (int i = 0; i < 10; i++) 
        cout << v[i] << " "; 
  
    // changes the size of the Vector 
    // but does not destroys the elements 
    v.resize(5); 
  
    cout << "\n\nVector size after resize(5): "
    << v.size(); 
  
    cout << "\nVector elements after resize(5) are: "; 
    for (int i = 0; i < 10; i++) 
        cout << v[i] << " "; 
  
    // Shrinks to the size 
    // till which elements are 
    // destroys the elements after 5 
    v.shrink_to_fit(); 
  
    cout << "\n\nVector size after shrink_to_fit(): "
    << v.size(); 
  
    cout << "\nVector elements after shrink_to_fit() are: "; 
    for (int i = 0; i < 10; i++) 
        cout << v[i] << " "; 
  
    return 0; 
}

输出：

Vector size initially: 10
Vector elements are: 0 1 2 3 4 5 6 7 8 9 

Vector size after resize(5): 5
Vector elements after resize(5) are: 0 1 2 3 4 5 6 7 8 9 

Vector size after shrink_to_fit(): 5
Vector elements after shrink_to_fit() are: 0 1 2 3 4 0 127889 0 0 0

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注：本文由纯净天空筛选整理自Twinkl Bajaj大神的英文原创作品 vector shrink_to_fit() function in C++ STL。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。