C++ vector::empty() 函数
vector::empty() 是 "vector" 头文件的库函数,用于检查给定的向量是否为空向量,如果向量大小为 0 则返回真,否则返回假。
注意:要使用矢量,请包括<vector>
标题。
vector::empty() 函数的语法
vector::empty();
参数: void
– 它不接受任何参数。
返回值: bool
– 如果向量大小为 0,则返回 true,否则返回 false。
例:
Input: vector<int> vector1{ 1, 2, 3, 4, 5 }; vector<int> vector2; Function call: cout << vector1.empty() << endl; cout << vector2.empty() << endl; Output: false true
C++程序演示vector::empty()函数的例子
//C++ STL program to demonstrate example of
//vector::empty() function
#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector<int> v1;
//printing the size of the vector
cout << "Total number of elements:" << v1.size() << endl;
//checking whether vector is empty or not
if (v1.empty())
cout << "vector is empty." << endl;
else
cout << "vector is not empty." << endl;
//pushing elements
v1.push_back(10);
v1.push_back(20);
v1.push_back(30);
v1.push_back(40);
v1.push_back(50);
//printing the size of the vector
cout << "Total number of elements:" << v1.size() << endl;
//checking whether vector is empty or not
if (v1.empty())
cout << "vector is empty." << endl;
else
cout << "vector is not empty." << endl;
return 0;
}
输出
Total number of elements:0 vector is empty. Total number of elements:5 vector is not empty.
参考:C++ vector::empty()
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注:本文由纯净天空筛选整理自 vector::empty() function with example 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。