C++ vector::swap()用法及代碼示例

C++ vector::swap() 函數

vector::swap() 是 "vector" 頭文件的庫函數，用於交換向量的內容，用一個向量調用它並接受另一個向量作為參數並交換它們的內容。 (兩個向量的大小可能不同)。

注意：要使用矢量，請包括<vector>標題。

vector::swap() 函數的語法

    vector::swap(vector& v);

參數： v– 與當前向量交換內容的另一個向量。

返回值： void——它什麽都不返回。

例：

    Input:
    vector<int> v1{ 10, 20, 30, 40, 50 };
    vector<int> v2{ 100, 200, 300 };
    
    //swapping content of the vectors
    v1.swap(v2);

    Output:
    //if we print the values
    v1:100 200 300
    v2:10 20 30 40 50

C++程序演示vector::swap()函數的例子

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

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

int main()
{
    //vector declaration
    vector<int> v1{ 10, 20, 30, 40, 50 };
    vector<int> v2{ 100, 200, 300 };

    //printing the sizes and values of the vectors
    cout << "before swap() call..." << endl;
    cout << "size of v1:" << v1.size() << endl;
    cout << "size of v2:" << v2.size() << endl;

    cout << "v1:";
    for (int x:v1)
        cout << x << " ";
    cout << endl;

    cout << "v2:";
    for (int x:v2)
        cout << x << " ";
    cout << endl;

    //swapping the content of the vectors
    v1.swap(v2);

    //printing the sizes and values of the vectors
    cout << "after swap() call..." << endl;
    cout << "size of v1:" << v1.size() << endl;
    cout << "size of v2:" << v2.size() << endl;

    cout << "v1:";
    for (int x:v1)
        cout << x << " ";
    cout << endl;

    cout << "v2:";
    for (int x:v2)
        cout << x << " ";
    cout << endl;

    return 0;
}

輸出

before swap() call...
size of v1:5
size of v2:3
v1:10 20 30 40 50
v2:100 200 300
after swap() call...
size of v1:3
size of v2:5
v1:100 200 300
v2:10 20 30 40 50

參考：C++ vector::swap()