text: #include <stdio.h>
  void inplace_swap(int *x, int *y);
  void inplace_swap(int *x, int *y){ //a = a, b = b
      // Remember that a ^ a = 0
      *y = *x ^ *y; // a = a, b = a ^ b
      *x = *x ^ *y; // a = a ^ a ^ b, b = a ^b --> a = 0 ^ b, b = a ^ b --> a = b, b = a ^ b
      *y = *x ^ *y; // a = b, b = a ^ b ^ b --> a  = b, b = a ^ 0 --> a = b, b = a
  
  }
  