Write a function to find length of a string?

/* A function to find length of a string */
/* length of string does not included '\0' character */

int length(char string[])
{
 int i=0, len;
 while(string[i] !='\0')
   ++i;
 if(i==0)
  len=0;
 else
  len=i;
 return(len);
} /* End of function length */