参考作为参数（References as Parameters）

我们已经讨论了如何使用指针实现call by reference概念。 这是另一个通过引用调用的例子，它使用C ++引用 -

#include <iostream>
using namespace std;
// function declaration
void swap(int& x, int& y);
int main () {
   // local variable declaration:
   int a = 100;
   int b = 200;
   cout << "Before swap, value of a :" << a << endl;
   cout << "Before swap, value of b :" << b << endl;
   /* calling a function to swap the values.*/
   swap(a, b);
   cout << "After swap, value of a :" << a << endl;
   cout << "After swap, value of b :" << b << endl;
   return 0;
}
// function definition to swap the values.
void swap(int& x, int& y) {
   int temp;
   temp = x; /* save the value at address x */
   x = y;    /* put y into x */
   y = temp; /* put x into y */
   return;
}

编译并执行上述代码时，会产生以下结果 -

Before swap, value of a :100
Before swap, value of b :200
After swap, value of a :200
After swap, value of b :100