C++ Function Definition Reverses a C-string

#include <iostream>
#include <cstring>                  //for strlen()
using namespace std;
int main()/*from  w  w w .j  a  v a  2  s  .co m*/
{
   void reversit( char[] );         //prototype
   const int MAX = 80;              //array size
   char str[MAX];                   //string
   cout << "\nEnter a string: ";    //get string from user
   cin.get(str, MAX);
   reversit(str);                   //reverse the string
   cout << "Reversed string is: ";  //display it
   cout << str << endl;
   return 0;
}
//function to reverse a string passed to it as an argument
void reversit( char s[] )
{
   int len = strlen(s);             //find length of string
   for(int j = 0; j < len/2; j++)   //swap each character
   {                             //   in first half
       char temp = s[j];             //   with character
       s[j] = s[len-j-1];            //   in second half
       s[len-j-1] = temp;
   }
}