stl vector 函数

C ++ vector :: back()函数 (C++ vector::back() function)

vector::back() is a library function of "vector" header, it is used to access the last element from the vector, it returns a reference to the last element of the vector.

vector :: back()是“ vector”标头的库函数，用于访问矢量的最后一个元素，它返回对矢量的最后一个元素的引用。

Note: To use vector, include <vector> header.

注意：要使用向量，请包含<vector>标头。

Syntax of vector::back() function

vector :: back()函数的语法

vector::back();

Parameter(s): none – It accepts nothing.

参数： 无 –不接受任何内容。

Return value: reference – It returns a reference to the last element of vector.

返回值： reference –返回对向量的最后一个元素的引用。

Example:

例：

Input:    vector
    
      vector1{ 1, 2, 3, 4, 5 };    Function call:    cout << vector1.back() << endl;    Output:    5
    

C ++程序演示vector :: back()函数的示例 (C++ program to demonstrate example of vector::back() function)

//C++ STL program to demonstrate example of//vector::back() function#include 
    
     #include 
     
      using namespace std;int main(){
       vector
      
        v1{
    10, 20, 30, 40, 50 };    //accessing last element    //using vector::back() function    cout << "last element is: " << v1.back() << endl;    //changing last element    v1.at(v1.size() - 1) = 100;    cout << "now, last element is: " << v1.back() << endl;    //changing last element    //using push_back()    v1.push_back(200);    cout << "now, last element is: " << v1.back() << endl;    return 0;}
      
     
    

Output

输出量

last element is: 50now, last element is: 100now, last element is: 200

Reference:

参考：

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stl vector 函数