#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <ctype.h>

bool get8bit(FILE * f, uint8_t * b);
void show8bit(uint8_t b);

void demo_operations(uint8_t b, uint8_t mask);

/* masks */
#define FOO (1)
#define BAR (1 << 5)

/* main program */
int main(void) {
	puts("enter 8-bit value (0s and 1s)");
	uint8_t b;
	if (!get8bit(stdin, &b)) { puts("invalid input"); return 1; }

	demo_operations(b, FOO);
	demo_operations(b, BAR);
	demo_operations(b, FOO | BAR);

	return 0;
}

/* 
 * get 8 chars (0 or 1) and convert to uint8_t
 * returns true if input is valid, false otherwise
 */
bool get8bit(FILE * f, uint8_t * b) {
	char bitchars[8];
	char next;
	if ((scanf("%8s%c", bitchars, &next) != 2) || !isspace(next)) {
		return false;
	}
	uint8_t work = 0;
	for (int i = 0; i < 8; ++i) {
		if (bitchars[i] == '0') { work <<= 1; }
		else if (bitchars[i] == '1') { work <<= 1; work+=1; }
		else return false;
	}
	*b = work;
	return true;
}


/* show 8 bits */
void show8bit(uint8_t b) {
	for (uint8_t mask = 1 << 7; mask > 0; mask >>= 1) {
		if (mask & b) 
			putchar('1') ;
		else 
			putchar('0');
	}
}

/* demo various operations -- setting, clearing, and testing bits */
void demo_operations(uint8_t b, uint8_t mask) {
	puts("value entered:");
	show8bit(b);
	putchar('\n');
	puts("mask:");
	show8bit(mask);
	putchar('\n');

	puts("result of setting all specified bits:");
	show8bit(b | mask); 
	putchar('\n');

	puts("result of clearing all specified bits:");
	show8bit(b & ~mask); 
	putchar('\n');

	printf("any bits set?  %c\n", 
			((b & mask) == 0) ? 'n' : 'y');

	printf("all bits set?  %c\n", 
			((b | mask) == b) ? 'y' : 'n');

	putchar('\n');
}