Bitwise Operators, Help!!

Hi I'm reading Ivor Horton's Beginning C, Third edition. And it came to Bitwise operations where I didn't quit understand this:

unsigned int original = 0xABC

what does it do, and how??

here is the rest of the source code if you what to have a look.

/* Program 3.10 Exercising bitwise operators */

#include <stdio.h>

void main()

{

unsigned int original = 0xABC;

unsigned int result = 0;

unsigned int mask = 0xF; /* Rightmost four bits */

printf("\n original = %X", original);

/* Insert first digit in result */

result |= original&mask; /* Put right 4 bits from original in result */

/* Get second digit */

original >>= 4; /* Shift original right four positions */

result <<= 4; /* Make room for next digit */

result |= original&mask; /* Put right 4 bits from original in result */

/* Get third digit */

original >>= 4; /* Shift original right four positions */

result <<= 4; /* Make room for next digit */

result |= original&mask; /* Put right 4 bits from original in result */

printf("\t result = %X\n", result);

}

Thank you