第一次结对代码

#include<stdio.h>


void div(int a, int b)
{
    int yushu, shang;
    shang = a / b;
    yushu = a - shang * b;
    printf("%d/%d=%d    余数为：%d\n", a, b, shang, yushu);
}
int jisuan(int a,char ch,int b)
{
    int c = 0;
    switch (ch)
    {
    case '+':
        c = a + b;
        printf("%d+%d=%d\n", a, b, c);
        break;
    case '-':
        c = a - b;
        printf("%d-%d=%d\n", a, b, c);
        break;
    case '*':
        c = a * b;
        printf("%d*%d=%d\n", a, b, c);
        break;
    case '/':
        div(a, b);
        c = a / b;
        break;
    }
    return c;
}
void xunhuan(int c)
{
    int i=1,j;
    char x='0',q;
    printf("如果需要进行下一步计算，请输入需要计算的数及运算符；格式如:' + 6'\n",c);
    printf("如果停止计算，请输入'.0'\n");
    while (i==1)
    { 
            scanf("%c%c%d",&q, &x, &j);
            if (x=='.')
            {   i = 0;
                printf("感谢使用");
            }
            else
            {
                c = jisuan(c, x, j);
            }
    }
}

int main()
{
  
    int i, a, b, c;
    char ch;
    a = 0;
    b = 0;
    ch = '0';
    printf("欢迎使用本计算器 \n");
    printf("请输入需要运行的功能的代码： \n");
    printf("代码1：简单四则运算 \n");
    printf("代码2：十进制转R进制 \n");
    printf("代码3：退出本计算器 \n");
    scanf("%d", &i);
    if (i == 1)
    {
        printf("请输入需要计算的数及运算符；格式如:'52 + 36' \n");
        scanf("%d%c%d", &a, &ch, &b);


        while ((ch != '+') && (ch != '-') && (ch != '*') && (ch != '/'))
        {
            printf("输入运算符有误，请重新输入运算符:\n");
            scanf("%c", &ch);
        }


        if ((ch == '/') && (b == 0))
        {
            printf("除数不能为0，请重新输入除数:\n");
            scanf("%d", &b);
        }
        c=jisuan(a,ch,b);
        xunhuan(c);

    }
    if (i == 2)
    {
        int i = 0, n, m;
        printf("请输入一个十进制数：\n");
        scanf("%i", &m);
        printf("请输入进制R：\n");
        scanf("%i", &n);

        int a[100];
        while (m)
        {
            a[i] = m % n;
            m = m / n;
            i++;
        }
        for (i = i - 1; i >= 0; i--)
        {
            if (a[i] == 10)
                printf("A");
            if (a[i] == 11)
                printf("B");
            if (a[i] == 12)
                printf("C");
            if (a[i] == 13)
                printf("D");
            if (a[i] == 14)
                printf("E");
            if (a[i] == 15)
                printf("F");
            if (a[i] != 10 && a[i] != 11 && a[i] != 12 && a[i] != 13 && a[i] != 14 && a[i] != 15)
                printf("%d", a[i]);
        }

    }
    return 0;
}