福尔摩斯的约会部分正确

以下是我的代码，希望指点

#include<stdio.h>
#include<string.h>
int main()
{
    char day,hour,a[61],b[61],c[61],d[61];
    int i,j,min;
    scanf("%s%s%s%s",a,b,c,d);
    for(i=0;i<strlen(a);i++)
    {
        if(a[i]==b[i]&&a[i]<='G'&&a[i]>='A')
        {
            day=a[i];
            j=i;
            break;
        }
    }
    for(i=j+1;i<strlen(a);i++)
    {
        if(a[i]==b[i]&&((a[i]>='0'&&a[i]<='9')||(a[i]>='A'&&a[i]<='N')))
        {
            hour=a[i];
            break;
        }
    }
    for(i=0;i<strlen(c);i++)
    {
        if(c[i]==d[i]&&((a[i]>='a'&&a[i]<='z')||(a[i]>='A'&&a[i]<='Z')))
        {
            min=i;
            break;
        }
    }
    switch(day)
    {
        case 'A':printf("MON ");break;
        case 'B':printf("TUE ");break;
        case 'C':printf("WED ");break;
        case 'D':printf("THU ");break;
        case 'E':printf("FRI ");break;
        case 'F':printf("SAT ");break;
        case 'G':printf("SUN ");break;
    }
    if(hour<='9'&&hour>='0')
    printf("%.2d:",hour-'0');
    else 
    printf("%d:",hour-'A'+10);
    printf("%.2d",min);
}