c++第七篇

#include<bits/stdc++.h>
using namespace std;
//函数的定义 
int add(int num1,int num2)
{
  int sum = num1 + num2;
  return sum;
}
void swap(int num1, int num2)
{
  cout << "交换前：" << endl;
  cout << "num1 = " << num1 << endl;
  cout << "num2 = " << num2 << endl;
  int temp = num1;
  num1 = num2;
  num2 = temp;
  cout << "交换后：" << endl;
  cout << "num1 = " << num1 << endl;
  cout << "num2 = " << num2 << endl;
  //return ; 当函数声明时候，不需要返回值，可以不写return
}
int main()
{
  //函数的调用
  int a1=add(2,3);
  cout<<a1<<endl;
  //函数值传递
  //函数的形参发生改变不影响实参
  int a = 10;
  int b = 20;
  swap(a, b);
  cout << "main中的 a = " << a << endl;
  cout << "main中的 b = " << b << endl;
  system("pause");
  return 0;
 }