Pangram Checking using C

pang.c

#include<stdio.h>
void main()
{
 int arr[26] = {0}; // Alphabet Array to count no of occurence        
 char str[] = "ABCDEFGHIJKLMNOPQRSTuvwxYZ"; //Input String
 int i = 10, count = 0, l = 0;
 //iterating every member of the input string
 for(i= 0; str[i] != '\0' ; i++)
    {
     l = str[i]; // Getting the ascii values 'a' = 97 and 'A' = 65
      if(l>=97 && l<=123) //Lower case Segregation 
       {
        arr[l-97]+=1;
        if(arr[l-97]==1) //Only check the variable for once, even if 'A' occurs say 'n' times, its first occurence counts
         {
          count++;
         }
       }
      else if(l>=65 && l<=91) // Upper case segregation
       {
        arr[l-65]+=1;
        if(arr[l-65]==1) 
         {
          count++;
         }
       }
    }
if(count==26) // if count == total no of alphabets ie 25 ubcluding 0
printf("yes");
else
printf("no");
}