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

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

  01000001    The ASCII code of uppercase 'A' is 65.
| 00100000    The mask 0x20 has 1 in bit position 5, and 0 everywhere else.
----------
  01100001    The ASCII code of lowercase 'a' is 97.
*/

int main()
{
	char c {'A'};   //Put 01000001 into c (in decimal, that's 65)
	cout << c << "\n";
	
	c |= 0x20;      //means c = c | 0x20;
	cout << c << "\n\n";

	char d {'B'};   //Put 01000010 into c (in decimal, that's 66)
	cout << d << "\n";
	d = tolower(d); //changes d to 98 (in binary, that's 01000010)
	cout << d << "\n";

	return EXIT_SUCCESS;
}