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

void swap(char* v1, char* v2)
{
	char temp;
	temp = *v1;
	*v1 = *v2;
	*v2 = temp;
}

void reverse(char* str)
{
	int i;
	int size = strlen(str);

	for(i = 0; i< size/2; i++)
	{
		swap(str+i, str+(size-i-1));
	}
}


int main()
{
	char c1, c2;
	char str[20];
	
	c1 = 'a', c2 = 'b'; 
	printf("Before swapping: c1 = %c, c2 = %c\n", c1, c2); 

	swap(&c1, &c2);
	printf("After swapping: c1 = %c, c2 = %c\n", c1, c2); 

	strcpy(str, "hello world!");
	printf("Original string: %s\n", str);

	reverse(str);
	printf("Reversed string: %s\n", str);

	return 0;
}