C program to reverse a string using pointers

Aim: Write a program to reverse a string using pointers in c

#include <stdio.h> 
#include <string.h> 
int main() 
{ 
    char str[100];
    int len, i; 
    char *begin, *end, ch; 
    printf("Enter a string: ");
    gets(str);
    
    len = strlen(str); 
    begin = str; 
    end = str; 
	
    for (i = 0; i < len - 1; i++) 
        end++;

    for (i = 0; i < len / 2; i++) { 
	    ch = *end; 
	    *end = *begin; 
	    *begin = ch; 
	    begin++; 
	    end--; 
    } 
    
    printf("Reverse of the string is: %s", str); 
    return 0; 
}

Another Approach

#include <stdio.h>
#include <string.h>
int main()
{
    char *s, str[10];
    int len, i;
    printf("Enter a string: ");
    gets(str);
    s=str;
    len = strlen(str);
    printf("The reverse of the string is: ");
    for (i = len; i >= 0; i--)
    {
        printf("%c", *(s + i));
    }
    return 0;
}