// Code to see the internal representation of an integer (signed or unsigned)
// Author: Sanjiv K. Bhatia
// Date  : February 27, 2003

#include <iostream>

// Count the number of bits used to represent an integer
// We do not want to use sizeof() operator; why?

uint num_bits_in_int()
{
    uint i ( 1 );		// Initialize integer to 1
    uint c ( 1 );		// Initialize count to 1

    while ( i <<= 1 )		// Look for overflow after shift left
	c++;

    return ( c );
}


// Main function

int main()
{
    using namespace std;

    int num;					// input number

    cout << "Please enter a number: ";
    cin >> num;

    uint nbits = num_bits_in_int();
    uint mask ( 1 << ( nbits - 1 ) );		// Mask initialized with MSB set

    cout << "The binary representation of " << num << " is: ";
    for ( uint i ( 0 ); i < nbits; i++ )
    {
	if ( ! ( i % 4 ) ) cout << " ";		// Space after four bits
	cout << ( ( num & mask ) ? 1 : 0 );	// Get appropriate bit in number
	mask >>= 1;				// Move bit in mask
    }
    cout << endl;

    // Hex representation; just for kicks

    cout << "The hex representation of " << num << " is: " << hex << num << endl;

    return ( 0 );
}