reverse_string.c

#include <stdio.h>
 
/* This function assumes the passed pointer points to a valid, zero-terminated string */
void reverse(char *s)
{
	char *t = s;
	
	while (*t != '\0') t++;
	
	while (s < t)
	{
		int c = *s;
		*s++ = *--t;
		*t = c;
	}
}
 
int main()
{
	char text1[] = "asdf", text2[] = "";
	
	reverse (text1);
	printf ("'%s'\n", text1);
	
	reverse (text2);
	printf ("'%s'\n", text2);
	
	return 0;
}