使用switch…case…语句实现
#define _CRT_SECURE_NO_DEPRECATE 1#include <stdio.h>#include <stdlib.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 x, y;int input = 1;int ret = 0;while (input){printf("*************************\n");printf("**** 1.add 2.sub ****\n");printf("**** 3.mul 4.div ****\n");printf("*************************\n");printf("请选择：");scanf("%d", &input);switch (input){case 1:printf("请输入操作数：");scanf("%d %d", &x, &y);ret = add(x, y);break;case 2:printf("请输入操作数：");scanf("%d %d", &x, &y);ret = sub(x, y);break;case 3:printf("请输入操作数：");scanf("%d %d", &x, &y);ret = mul(x, y);break;case 4:printf("请输入操作数：");scanf("%d %d", &x, &y);ret = div(x, y);break;default:printf("选择错误\n");break;}printf("%d\n", ret);}system("pause");return 0;}
使用函数指针数组实现
由于加减乘除四个函数的函数类型都一样，因此我们可以把它们的地址放在一个函数指针数组里面，通过下标来访问函数。
函数指针数组的用途：转移表
具体代码如下：
#define _CRT_SECURE_NO_DEPRECATE 1#include <stdio.h>#include <stdlib.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 x, y;int input = 1;int ret = 0;int(*p[5])(int x, int y) = {0, add, sub, mul, div };//转移表while (input){printf("*************************\n");printf("**** 1.add 2.sub ****\n");printf("**** 3.mul 4.div ****\n");printf("*************************\n");printf("请选择：");scanf("%d", &input);if (input<4 && input>1){printf("请输入操作数：");scanf("%d %d", &x, &y);ret = (*p[input])(x, y);}elseprintf("输入有误\n");printf("ret = %d", ret);}system("pause");return 0;}
