用C语言设计计算器：实现加减乘除

方法一：通过普通方法：

#include<stdio.h> #include<windows.h> int add(int x, int y) { return x + y; } int sub(int x, int y) { return x - y; } int nul(int x, int y) { return x*y; } int drv(int x, int y) { return x / y; } int main(){ int x, y; int input = 1; int ret = 0; while (input){ printf("***********************\n"); printf(" 1:add 2:sub \n"); printf(" 3:nul 4:div \n"); printf("***********************\n"); printf("请选择："); scanf_s("%d", &input); switch (input){ case 1: { printf("输入的数："); scanf_s("%d%d", &x, &y); ret = add(x, y); }; break; case 2: { printf("输入的数："); scanf_s("%d%d", &x, &y); ret = sub(x, y); }; break; case 3: { printf("输入的数："); scanf_s("%d%d", &x, &y); ret = nul(x, y); }; break; case 4: { printf("输入的数："); scanf_s("%d%d", &x, &y); ret = drv(x, y); }; break; default: printf("输入错误，请重新输入！\n"); } printf("%d\n", ret); } system("pause"); return 0; } #include<stdio.h> #include<windows.h>