C program to count no. of uppercase and lowercase letters in a string

PROGRAM:

#include <stdio.h>
int main()
{
    char str[50];
    int i=0,upper=0,lower=0;
    printf("Enter a string\n");
    scanf("%s",str);
    printf("Entered string is %s\n",str);
    while(str[i]!='\0')
    {
        if(str[i]>='A'&&str[i]<='Z')
            upper++;
        if(str[i]>='a'&&str[i]<='z')
            lower++;
        i++;

    }
    printf("No. of uppercase letters=%d\n",upper);
    printf("No. of lowercase letters=%d\n",lower);
    return 0;
}

OUTPUT:

Enter a string
SatyamevJayate
Entered string is SatyamevJayate
No. of uppercase letters=2
No. of lowercase letters=12