同学，不能用值传递啊。值传递是单向的实参->形参，参数的值只能传入，不能传出，建议用指针传递，个人建议&传递。

望采纳！

#include <iostream>

using namespace std;

//按值传递 

void swap1(int &x, int &y)//值传递是单向传递，实参->形参，参数的值只能传入，不能传出，建议用指针传递，个人建议&传递。

{

int temp;

temp = x;

x = y;

y = temp;

}

//按址传递 

void swap2(int *x, int *y)

{

int temp;

temp = *x;

*x = *y;

*y = temp;

}

//按引用传递 

void swap3(int &x, int &y)

{

int temp;

temp = x;

x = y;

y = temp;

}

int main()

{

int a = 1, b = 2;

int c = 3, d = 4;

int e = 5, f = 6;

cout << "交换前：a=" << a << "，b=" << b << endl;

cout << "按值传递交换a和b。\n";

swap1(a, b);

cout << "交换后：a=" << a << "，b=" << b << endl;

cout << "\n";

cout << "交换前：c=" << c << "，d=" << d << endl;

cout << "按址传递交换c和d。\n";

swap2(&c, &d);

cout << "交换后：c=" << c << "，d=" << d << endl;

cout << "\n";

cout << "交换前：e=" << e << "，f=" << f << endl;

cout << "按引用传递交换e和f。\n";

swap3(e, f);

cout << "交换后：e=" << e << "，f=" << f << endl;

return 0;

}