cs3710a1q1

cs3710a1q1.c

/*Question 1: Bitwise operators*/

#define INT_SIZE (sizeof(int) * 8)

#include <stdio.h>

/* Helper function to print a binary representation of an unsigned integer */
void print_int_as_binary_string(unsigned int b) {
	int i;
	char buffer[INT_SIZE + 1];
	buffer[INT_SIZE] = '\0';
	
	for (i = 31; i >= 0; i--) {
		/* Adds 1 to the char '0' if bit is 1 to make the char a '1' */
		buffer[i] = ((b >> ((INT_SIZE - 1) - i)) & 0x1) + '0';
	}
	printf("%s\n", buffer);
}


unsigned invert(unsigned int x, unsigned int p, unsigned int n){
		int i;
		for(i = p; i < p + n; i++){
			x ^= (0x1 << INT_SIZE - i); /* XOR with a shifted bit mask */
		}
		return x;
}


int main (int argc, char *argv[]) {
	
	int number = atoi(argv[1]);
	int start = atoi(argv[2]);
	int length = atoi(argv[3]);
	
	// check for invalid input
	if (start < 1 || length < 1 || start + length > INT_SIZE + 1) {
		printf("Invalid start or length provided.\n");
		return 0;
	}
	
	print_int_as_binary_string(number);
	print_int_as_binary_string(invert(number, start, length));
	
	return 1;

}