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reference: 

Problem Definition:

Write a program to print Binary representation of a given number.

Solution:

This is a simple problem, the reason why it is posted here is because it was a MS Interview question. Obviously, we can do it both in iterative and recursive way.

Iterative way: 

1) Let us take number 'NUM' and we want to check whether it's 0th bit is ON or OFF		bit = 2 ^ 0 (0th bit)	if  NUM & bit == 1 means 0th bit is ON else 0th bit is OFF2) Similarly if we want to check whether 5th bit is ON or OFF		bit = 2 ^ 5 (5th bit)	if NUM & bit == 1 means its 5th bit is ON else 5th bit is OFF.

Recursive way: 

step 1) if NUM > 1	a) push NUM on stack	b) recursively call function with 'NUM / 2'step 2)	a) pop NUM from stack, divide it by 2 and print it's remainder.

Code:

Iterative code:

void bin(unsigned n){    unsigned i;    for (i = 1 << 31; i > 0; i = i / 2)        (n & i)? printf("1"): printf("0");}

recursive code:

void bin(unsigned n){    /* step 1 */    if (n > 1)        bin(n/2);     /* step 2 */    printf("%d", n % 2);}

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