C program to count Uppercase, Lowercase, Digit and Special character

In this program, you will take string input from user and finding all occurrence of uppercase, lowercase, digit and special character from a given string.

#include<stdio.h>
int main()
{
    char a[30];
    int u=0,l=0,s=0,d=0,i;
    printf("\nenter the string:");
    gets(a);
    for(i=0;a[i]!='\0';i++)
    {
        if(a[i]>='A' && a[i]<='Z')
        u++;
        else if(a[i]>='a' && a[i]<='z')
            l++;
        else if(a[i]>='1' && a[i]<='9')
            d++;
        else{
            s++; }
    }
    printf("\nuppercase:%d",u);
    printf("\nlowercase:%d",l);
    printf("\ndigit:%d",d);
    printf("\nspecial character:%d",s);
    return 0;
}

output

enter the string:[email protected]@come12
uppercase:2
lowercase:5
digit:2
special character:2