#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Sort given string in-place and return it
char* strrev(char s[])
{
	int c, i, j;

	for (i = 0, j = strlen(s) - 1; i < j; i++, j--)
	{
		c = s[i];
		s[i] = s[j];
		s[j] = c;
	}
	return s;
}

int main(int argc, char **argv)
{
	char str[] = "HelloWorld";
	printf("%s\n", strrev(str));
	return 0;
}