前端知识笔记（四十）———用C语言实现计算器功能

#include<stdio.h>
int add(int x, int y)
{
  return x + y;
}
int sub(int x, int y)
{
  return x - y;
}
int mul(int x, int y)
{
  return x * y;
}
int div(int x, int y)
{
  return x / y;
}
int main()
{
  int input = 1;
  int a, b, ret;
  do
  {
    printf("*****************************\n");
    printf("**1.add     2.sub ***********\n");
    printf("**3.mul     4.div ***********\n");
    printf("**0.exit          ***********\n");
    printf("*****************************\n");
    scanf("%d", &input);
    switch (input)
    {
    case 1:
      printf("请输入操作数：");
      scanf("%d %d", &a, &b);
      ret = add(a, b);
      printf("ret=%d\n", ret);
      break;
    case 2:
      printf("请输入操作数：");
      scanf("%d %d", &a, &b);
      ret = sub(a, b);
      printf("ret = %d\n", ret);
      break;
    case 3:
      printf("请输入操作数：");
      scanf("%d %d", &a, &b);
      ret = mul(a, b);
      printf("ret = %d\n", ret);
      break;
    case 4:
      printf("请输入操作数：");
      scanf("%d %d", &a, &b);
      ret = div(a, b);
      printf("ret = %d\n", ret);
      break;
    case 0:
      printf("退出游戏");
      break;
    default:
      printf("选择错误");
      break;
    }
  } while (input);
  return 0;
}