// Reverse a string using pointers:
#include <stdio.h>
void rev(char *str)
{
char *r_ptr = str;
while (*(r_ptr + 1) != ' ')
r_ptr++;
while (r_ptr > str)
{
char tmp = *r_ptr;
*r_ptr-- = *str;
*str++ = tmp;
}
}
void main()
{
char s[] = "Hello World!";
rev(s);
puts(s); // Prints !dlroW olleH
}