String length using pointers

#include<stdio.h>

int string_length(char *a) 
{ 	 int i=0;
  while(*a!='\0') 
  { i++;
    a++;
  }
    return i;
  } 

int main() 
{  
  char *s; 
  int l;
   printf("enter a string\n"); 
   gets(s);
   l=string_length(s); 
   printf("l=%d",l);
 }

     

           

Note: Need to be arranged in compiler after copied

   

 OutPut:

enter a string Hello l=5