在VS上面怎么试都是对的呀，为啥是0分呜呜呜

#include<stdio.h>
#include<math.h>
int weishu(int n);
int isalpha(char a);
int main()
{
    int i, b[50], c[50], r=0;
    char a[50];
    scanf("%d",&i);
    getchar();
    for (int j = 0;j < i;j++)
    {
        scanf("%c", &a[j]);
        if (isalpha(a[j]))
            scanf(" %d %d", &b[j], &c[j]);
        else
        {
            scanf("%d %d", &b[j], &c[j]);
            int t = a[j] - '0';
            b[j] = t * pow(10, weishu(b[j])) + b[j];
            a[j] = a[j - 1];
        }
        getchar();
    }
    for (int j = 0;j < i;j++)
    {
        switch (a[j])
        {
        case'a':
        {
            r = b[j] + c[j];
            printf("%d+%d=%d\n", b[j], c[j], r);
        }
        break;
        case'b':
        {
            r = b[j] - c[j];
            printf("%d-%d=%d\n", b[j], c[j], r);
        }
        break;
        case'c':
        {
            r = b[j] * c[j];
            printf("%d*%d=%d\n", b[j], c[j], r);
        }
        break;
        }
        int w = weishu(b[j]) + weishu(c[j]) + weishu(r) + 2;
        if (j != i - 1)
            printf("%d\n", w);
        else
            printf("%d", w);
    }
    return 0;
}
int weishu(int n)
{
    int c = 1;
    if (n / 10)
        c = 2;
    if (n / 100)
        c = 3;
    if (n / 1000)
        c = 4;
    if (n < 0)
        c += 1;
    return c;
}
int isalpha(char a)
{
    int c = 0;
    if (a>='a'&& a<='z')
        c = 1;
    return c;
}