Question

Quick question. I’ve never had experience with C.

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

int main()
{
   int n, x;
   printf( "How many disks? " );
   scanf( "%d", &n );
   printf("\n");
   for (x=1; x < (1 << n); x++)
      printf( "move from tower %i to tower %i.\n",(x&x-1)%3, ((x|x-1)+1)%3 );
    return 0;
}

This is an iterative tower of hanoi. What do things like (x&x-1) and (x|x-1)+1 mean? I figure the % is doing modulus. and %i is a way of printing out integers in C?

Thanks

Answer 1

What do things like (x&x-1) and (x|x-1)+1 mean?

(x&x-1) is equivalent to (x & (x-1)). & is the bitwise-AND operator. Similarly for the second example, where | is the bitwise-OR operator.

I figure the % is doing modulus.

Yes.

and %i is a way of printing out integers in C?

Yes.