Write a program to find length of a string without using library functions

Write a program to find length of a string without using library functions.

1. #include <stdio.h>
2. void main()
3. {
4.     char str[100];
5.     int i, len = 0;
6.  
7.     printf("Please enter a string : ");
8.     scanf("%s", str);
9.    
10.     for (i = 0; str[i] != '\0'; i++) {
11.         len++;
12.     }
13.     printf("The length of a string is : %s = %d\n", str, len);
14. }