c语言计算器两种方法

//一般做法
#include<stdio.h>
#include<windows.h>
//#include<assert.h>
void menu()
{printf("**************************\n");printf("****欢迎来到计算器页面****\n");printf("**** 1.add    2.mul  *****\n");printf("*****3.sub    4.div1 *****\n");printf("*****0.exit          *****\n");printf("**************************\n");
}int add(int x, int y)
{return x + y;
}int mul(int x, int y)
{return x * y;
}int sub(int x, int y)
{return x - y;
}int div1(int x, int y)
{return x / y;
}int main()
{int n = 1;menu();while (n){printf("请输入选项:\n");scanf("%d", &n);int x = 0, y = 0;/*printf("请输入两个整数!\n");scanf("%d%d", &x, &y);*/    //若将两个数字输入放在此处会出现输入错误时不能退出系统，而是显示“输入两个整数”的提示switch (n){case 1:printf("请输入两个整数!\n");scanf("%d%d", &x, &y);printf("%d\n", add(x, y));break;case 2:printf("请输入两个整数!\n");scanf("%d%d", &x, &y);printf("%d\n", mul(x, y));break;case 3:printf("请输入两个整数!\n");scanf("%d%d", &x, &y);printf("%d\n", sub(x, y));break;case 4:printf("请输入两个整数!\n");scanf("%d%d", &x, &y);printf("%d\n", div1(x, y));break;case 0:printf("退出计算器！\n");break;default:printf("输入错误，请重新输入!\n");}}
}

//使用函数指针数组解决计算器问题#include<stdio.h>
#include<windows.h>
//#include<assert.h>void menu()
{printf("**************************\n");printf("****欢迎来到计算器页面****\n");printf("**** 1.add    2.mul  *****\n");printf("*****3.sub    4.div1 *****\n");printf("*****0.exit          *****\n");printf("**************************\n");
}int add(int x, int y)
{return x + y;
}int mul(int x, int y)
{return x * y;
}int sub(int x, int y)
{return x - y;
}int div1(int x, int y)
{return x / y;
}int main()
{int n = 1;menu();while (n){printf("请输入选项:\n");scanf("%d", &n);int(*arr[5])() = { 0,add,mul,sub,div1 };//转移表//定义一个函数指针数组，存放函数地址if (n >= 0 && n < 5){int x = 0, y = 0;printf("请输入两个整数:>\n");scanf("%d%d", &x, &y);printf("%d\n", (*arr[n])(x,y));//输出结果}else{printf("输入有误，请重新输入!\n");scanf("%d", &n);}}system("pause");return 0;
}

两种方法相比，第一种相似代码较多，比较冗余；第二种代码简洁直观，程序效率高。