#include <cmath>
#include <iomanip>
#include <iostream>

// Thanks to: https://stackoverflow.com/questions/111928/is-there-a-printf-converter-to-print-in-binary-format
#define BYTE_TO_BINARY_PATTERN "%c%c%c%c%c%c%c%c"
#define BYTE_TO_BINARY(byte)  \
  (byte & 0x80 ? '1' : '0'), \
  (byte & 0x40 ? '1' : '0'), \
  (byte & 0x20 ? '1' : '0'), \
  (byte & 0x10 ? '1' : '0'), \
  (byte & 0x08 ? '1' : '0'), \
  (byte & 0x04 ? '1' : '0'), \
  (byte & 0x02 ? '1' : '0'), \
  (byte & 0x01 ? '1' : '0') 

// Thanks to: http://www.cplusplus.com/forum/beginner/85527/#msg458803
union {
	double dbl;
	unsigned __int8 shortInt[sizeof(double)];
} test;

void displayBits(int, unsigned short[]);

int main() {

	double dbl;
	std::cout << "Enter a double precision number: ";
	std::cin >> dbl;

	test.dbl = dbl;

	unsigned short revShortInt[sizeof(double)];
	for (int i = 0; i < 8; i++) {
		revShortInt[7 - i] = test.shortInt[i];
	}

	displayBits(sizeof(double), revShortInt);

	int signBit = (revShortInt[0] & 0b10000000) >> 7;

	int exponentBits = ((int)((revShortInt[0] & 0b01111111) << 4))
		| (int)(revShortInt[1] & 0b11110000) >> 4;

	unsigned long long int fraction = ((long long int)(revShortInt[1] & 0b00001111) << 48) |
		((unsigned long long int)(revShortInt[2]) << 40) |
		((unsigned long long int)(revShortInt[3]) << 32) |
		((unsigned long long int)(revShortInt[4]) << 24) |
		((unsigned long long int)(revShortInt[5]) << 16) |
		((unsigned long long int)(revShortInt[6]) << 8) |
		(revShortInt[7]);

	long long int onedFraction = fraction | 0x10000000000000;

	std::cout << "myDouble: " << std::setprecision(16) << test.dbl << std::endl;
	std::cout << "signBit: " << signBit << std::endl;
	std::cout << "exponentBits: " << exponentBits << std::endl;
	std::cout << "fraction: " << fraction << std::endl;

	double expValue = std::pow(2, exponentBits - 1023);
	std::cout << "expValue: " << expValue << std::endl;

	double oneValue = (std::pow(2, -52) * onedFraction);
	printf("oneValue: %f\n", oneValue);
	double newValue = expValue * oneValue;
	std::cout << "newValue: " << newValue << std::endl;

	std::cin.get();

	return 0;
}

void displayBits(int numberOfBytes, unsigned short bits[]) {
	for (int i = 0; i < numberOfBytes; i++) {
		printf("   %02x    ", bits[i]);
	}
	std::cout << std::endl;

	for (int i = 0; i < numberOfBytes; i++) {
		printf(BYTE_TO_BINARY_PATTERN" ", BYTE_TO_BINARY(bits[i]));
	}
	std::cout << std::endl;

	int bitCount = numberOfBytes * 8 - 1;

	for (int i = bitCount; i >= 0; i--) {
		std::cout << i / 10;
		if (i % 8 == 0) {
			std::cout << ' ';
		}
	}
	std::cout << std::endl;

	for (int i = bitCount; i >= 0; i--) {
		std::cout << i % 10;
		if (i % 8 == 0) {
			std::cout << ' ';
		}
	}
	std::cout << std::endl << std::endl;
}