.编两个子函数，分别用指针和引用实现主程序两个交换。

好的，我可以为您编写这两个子函数。

使用指针实现交换：

#include <iostream>
using namespace std;

void swap_ptr(int *a, int *b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}

int main() {
    int x = 5, y = 10;
    cout << "Before swap: x = " << x << ", y = " << y << endl;
    swap_ptr(&x, &y);
    cout << "After swap: x = " << x << ", y = " << y << endl;
    return 0;
}

使用引用实现交换：

#include <iostream>
using namespace std;

void swap_ref(int &a, int &b) {
    int temp = a;
    a = b;
    b = temp;
}

int main() {
    int x = 5, y = 10;
    cout << "Before swap: x = " << x << ", y = " << y << endl;
    swap_ref(x, y);
    cout << "After swap: x = " << x << ", y = " << y << endl;
    return 0;
}

这两个程序的输出是相同的：

Before swap: x = 5, y = 10
After swap: x = 10, y = 5