#include <iostream>
#include <cstdlib>
#include <cctype>   //for the function toupper
using namespace std;

/*
Use "bitwise and" to change the character lowercase 'a' to uppercase 'A'.
(We're really changing the number 97 to 65.)
The "bitwise and" turns off bit number 5 of the character c,
converting it from lower to uppercase.

  01100001 The ASCII code of lowercase 'a' is 97.
& 11011111 The mask 0xDF has 0 in bit position 5, and 1 everywhere else.
----------
  01000001 The ASCII code of uppercase 'A' is 65.
*/

int main()
{
	char c {'a'};   //Put 01100001 into c (in decimal, that's 97)
	cout << c << "\n";
	
	c &= 0xDF;      //means c = c & 0xDF;
	cout << c << "\n\n";

	char d {'b'};   //Put 01100010 into d (in decimal, that's 98) 
	cout << d << "\n";
	d = toupper(d); //changes d to 01000010 (in decimal, that's 66)
	cout << d << "\n";

	return EXIT_SUCCESS;
}