/* File: bitop.c
   bitop.c is an equivalent C program for the Ch program bitop.ch
   without using the printing format "%b" and binary constant 0bxxxx. 
   Apply bitwise operators to variables with 1 byte */
#include <stdio.h>

/* function printbits() prints each bit of the passed argument 'c' */
int printbits(char c) {
    int mask,   /* declare mask */
        num,    /* num of bits for the passed variable */
        i,      /* index variable for the for-loop */
        bit;    /* the binary value 1 or 0 for a bit */
    num = sizeof(char)*8;/* number of bits for a char, 8 bits for a byte */
    /* Assume bit positions are [8 7 6 5 4 3 2 1].  Obtain the binary 
       value 1 or 0 at each position, starting with the most left bit */
    for(i=num; i>=1 ; i--) {
        mask = 1 << (i-1); /* (i)th bit of mask is 1 
        /* (i)th bit of (c & mask) is 1 only if (i)th bit of c is 1, 
           (c & mask) != 0 is 1; Otherwise, it is 0. */
        bit = (c & mask) != 0;
        printf("%d", bit); /* print either 1 or 0 for the value of bit */
    }
    printf("\n");
    return 0;
}

int main() {
    /* declare variables and initialize with hexadecimal numbers */
    char a = 0xB4;    /*  0xB4 is 0b10110100 */
    char b = 0xD9, c; /*  0xD9 is 0b11011001 */

    /* apply bitwise operators to variables a and b */
    printf("a =      0b");
    printbits(a);
    printf("b =      0b");
    printbits(b);
    c = a & b;
    printf("a & b =  0b");
    printbits(c);
    c = a | b;
    printf("a | b =  0b");
    printbits(c);
    c = a ^ b;
    printf("a ^ b =  0b");
    printbits(c);
    c = b << 1;
    printf("a <<b =  0b");
    printbits(c);
    c = a >> 1;
    printf("a >>b =  0b");
    printbits(c);
    c = ~a;
    printf("~a =     0b");
    printbits(c);
    return 0;
}