Cracking the Coding Interview 1-2

#include <iostream>
#include <algorithm>

using namespace std;

void reverse(char* str) {
  int length = strlen(str);
  char* str_head = str;
  char* str_tail = &str[length-1];
  while(str_head < str_tail) swap(*str_head++,*str_tail--);
}

int main(int argc, const char * argv[])
{
  char str[256] = "Hel";
  reverse(str);
  cout << str << endl;
  return 0;
}