Palindrome checking without using string.h

Contributed by pradeep () On 3rd February, 2007

This is an article on Palindrome checking without using string.h in C.

One of my friends, who is learning to program in C, asked me about how to write a program which checks an inputed string is a palindrome or not, without using the header file string.h

So here's the solution.

Code: C

#include <stdio.h>

void main(void)
{
    char str[50];
    int len=0,i=0,j,flag=1;
    
    printf("Enter a string: ");
    gets(str);
    
    while(str[i++]!='\0')
        len++;

    for(i=0,j=(len-1);i<len/2;i++,j--)
    {
        if(str[j]!=str[i])
        {
            flag=0;
            break;
        }
    }
        
    if(flag==1)
        printf("String is a palindrome");
    else
        printf("String is not a palindrome");

}