一个计算器

#include <stdio.h> 
#include <stdlib.h>

void addition()
{
    int a, b;
    printf("请输入2个数字：\n");
    scanf("%d%d", &a, &b);
    printf("%d + %d = %d\n", a, b, a + b);
}

void substraction()
{
    int a, b;
    printf("请输入2个数字：\n");
    scanf("%d%d", &a, &b);
    printf("%d - %d = %d\n", a, b, a - b);
}

void multiplication()
{
    int a, b;
    printf("请输入2个数字：\n");
    scanf("%d%d", &a, &b);
    printf("%d * %d = %d\n", a, b, a * b);
}

void division()
{
    int a, b;
    printf("请输入2个数字：\n");
    scanf("%d%d", &a, &b);
    while (b == 0)
    {
        printf("请重新输入：\n");
        scanf("%d%d", &a, &b);
    }
    printf("%d / %d = %d …… %d", a, b, a / b, a % b);
}

void operation()
{
    printf("输入数字选择对应的运算操作符\n");
    printf("1:加法\t2:减法\n3:乘法\t4:除法\n0:退出\n");
    int opera = 0;
    scanf("%d", &opera);
    try
    {
        if (opera == 1)
        {
            addition();
        }
        else if (opera == 2)
        {
            substraction();
        }
        else if (opera == 3)
        {
            multiplication();
        }
        else if (opera == 4)
        {
            division();
        }
        else if (opera == 0)
        {
            exit(0);
        }
        else
        {
            throw 1;
        }
    }
    catch (int i)
    {
        printf("输入错误\n");
    }
    operation();
}

int main()
{
    printf("欢迎使用计算机器！\n");
    operation();
    return 0;
}