C++ vector::clear()用法及代碼示例

C++ vector::clear() 函數

vector::clear() 是 "vector" 頭文件的庫函數，用於移除/清除向量的所有元素，在移除所有元素後生成 0 大小的向量。

注意：要使用矢量，請包括<vector>標題。

vector::clear() 函數的語法

    vector::clear();

參數： none——它什麽都不接受。

返回值： void——它什麽都不返回。

例：

    Input:
    vector<int> v1{ 10, 20, 30, 40, 50 };
    
    //clearing content of the vectors
    v1.clear();
    cout <> v1.size();

    Output:
    0

C++程序演示vector::clear()函數的例子

//C++ STL program to demonstrate example of
//vector::clear() function

#include <iostream>
#include <vector>
using namespace std;

int main()
{
    //vector declaration
    vector<int> v1{ 10, 20, 30, 40, 50 };

    //printing elements
    cout << "before clearing the elements..." << endl;
    cout << "size of v1:" << v1.size() << endl;
    cout << "v1:";
    for (int x:v1)
        cout << x << " ";
    cout << endl;

    //clearing all elements
    v1.clear();

    //printing elements
    cout << "after clearing the elements..." << endl;
    cout << "size of v1:" << v1.size() << endl;
    cout << "v1:";
    for (int x:v1)
        cout << x << " ";
    cout << endl;

    return 0;
}

輸出

before clearing the elements...
size of v1:5
v1:10 20 30 40 50
after clearing the elements...
size of v1:0
v1:

參考：C++ vector::clear()