C program to find string length

This program prints length of string, for example consider the string "c programming" it's length is 13. Null character is not counted when calculating string length. To find string length we use strlen function of string.h.

C program to find string length

#include <stdio.h>
#include <string.h>
 
int main()
{
   char a[100];
   int length;
 
   printf("Enter a string to calculate it's length\n");
   gets(a);
 
   length = strlen(a);
 
   printf("Length of entered string is = %d\n",length);
 
   return 0;
}

Download String length program.
Output of program:

You can also find string length using pointer or without strlen function. Following program shows how to achieve this.

C program to find string length without strlen

C program to find length of a string using pointers.

#include <stdio.h>
 
int main()
{
   char array[100], *pointer;
   int length = 0;
 
   printf("Enter a string\n");
   gets(array);
 
   pointer = array;
 
   while(*(pointer+length))
      length++;
 
   printf("Length of entered string = %d\n",length);
 
   return 0;
}

Function to find string length

int string_length(char *s)
{
   int c = 0;
 
   while(*(s+c))
      c++;
 
   return c;
}