need help in the string length function

here is my code to find out the length of the string.

#include <stdio.h>
#include <stdlib.h>

int main()
{
char st[ ]=“hithere”;
printf("\a");
int i;
i=len(st);
printf("%s",st);
printf("\a%d",i);
return 0;
}
int len(char *s)
{
int l=0;
while(*s != ‘\0’);
{

 l++;        
 s++;      

}

return (l);
}

cant figure out the problem please help.
(making in codeblocks)

In your len function, you were accessing a character not a pointer. so s++ is next character alphabetically not next character of the string. if your parameter is accepting a pointer then s++ would be next element of string or character array

include <stdio.h>
include <stdlib.h>
int main() 
{ 
 char st[ ]="hithere"; 
 printf("\a"); 
 int i; 
 i=len(st); 
 printf("%s",st); 
 printf("\a%d",i); 
 return 0; 
} 
int len(char s[]) // or(char *s) 
{ 
int l=0; 
while(s != '\0'); 
{
 l++;        
 s++;
}
return (l); 
}