Go4Expert - C Program to Calculate all possible Combinations of an n Digit Number

Generally a question is asked that if you have given n bits then print out all the possible binary numbers of n bit and so I will try to explain how to get that done. Please don't Copy Paste. Understand The logic because it is useful in other problems as well

for eg
if n=1 then you can have
0
1
if n=2 then you can have
00
10
01
11

Similarly if n=3 then you can have 8 possible combination.

In general for a n bit number you can have 2 to the power n possible numbers. :D

Code:

#include <stdio.h>

#define ARRAY_SIZE 200

/* FUNCTIONS DECLARATIONS */

void find_all_possible_binary(int ,int );

void push(int );

void pop();



/******************************************************************************

* SIMPLE LIFO STACK .YOU CAN ADJUST ARRAY_SIZE ACCORDING TO YOUR SYSTEM MEMORY

replace pf with printf

*/

int stack[ARRAY_SIZE];

int top;



void push(int x){

        stack[++top]=x;

}



void pop(){

        stack[top--];

}

/******************************************************************************/



void find_all_possible_binary(int x,int temp)

{

        int i;

        if(temp!=-1){

                push(temp);

        } 

        if(x==0){

                for( i=0;i<=top;++i)

                        pf("%d",stack[i]);

                pf("\n");

                pop();

        }

        else{   

                find_all_possible_binary(x-1,0);

                find_all_possible_binary(x-1,1);

                pop();        

        }

}

int main(){

        int no_of_bits;

        top=-1;

        pf("Enter number of bits: ");

        scanf("%d",&no_of_bits);

        find_all_possible_binary(no_of_bits,-1);

}