Thread: Store a binary number to an array

I know there are a ton of this problems in google search(decimal to binary) but i cant find something the way I want .
So this is my code i dont know why it does nt work, can someone help me?

Code:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>


#define MAX 20


int input_dec(){
    int x=0;
    scanf("%d", &x);
    if ( x >= 0)
        return x;
    else
        return x = -1;
}


int dec2bin(int m, int b[]){
    int i = MAX - 1 , counter = 0, y=0;


    b[MAX] = m % 2;//The first binary number
    y = m / 2;


    while( y != 0){
        b[i] = y % 2 ;
        i--;
        y = y / 2 ;
        counter++;
        if(counter == MAX+1 )break;
    }
    if(counter == MAX+1 )return -1;
    else{
        b[i] = -1 ;
        return 1;
    }


}


void print_bin(int b[]){
    int i = 0, hold =0;
    printf("\n");
    for(i=0; i <= MAX; i++){
        if ( hold == -1 ){
            printf("%d", b[i]);
        }
        if ( b[i] == -1 ){
            hold = b[i];
        }
    }


}


int add_bin(int b1[], int b2[], int b_tot[]){
    int i = 0, counter = 0, counter1= 0, counter2 = 0, hold1 = 0, pos1 = 0, hold2 = 0, pos2 = 0, sub = 0;


    //control for equal binary digits
    for(i = 0; i <= MAX; i++){
        if ( hold1 == -1)counter1++;


        if ( hold2 == -1)counter2++;


        if ( b1[i] == -1 ){
            hold1 = b1[i];
            pos1 = i;
        }
        if ( b2[i] == -1){
            hold2 = b2[i];
            pos2 = i;
        }
    }
    //putting the necessary '0' to get equal binary digits
    sub = counter1 - counter2 ;
    //when second binary number is bigger
    if ( sub < 0) {
        sub = abs(sub);
        for( i = MAX; i >= 0; i--){
            if ( hold1 == 0 ) {
                b1[i] = 0;
                sub--;
                if ( sub == 0)break;
            }
            if (i  == pos1){
                b1[i] = 0;
                hold1 = 0;
                sub--;
                if( sub == 0)break;
            }
        }
        b1[ i-1 ] = -1;
    }
    else{
        for( i = MAX; i >= 0 ; i--){
            if ( hold2 == 0 ) {
                b2[i] = 0;
                sub--;
                if ( sub == 0)break;
            }
            if (i  == pos2){
                b2[i] = 0;
                hold2 = 0;
                sub--;
                if( sub == 0)break;
            }
        }
        b2[ i-1 ] = -1;
    }


    //ADD
    for( i = MAX ; i >= 0 ; i--){
        if ( b1[i] == 0 && b2[i] == 0 ){
            b_tot[i] = 0;
            if ( hold1 ) b_tot[i] = 1;
        }
        if ( b1[i] == 0 && b2[i] == 1){
            b_tot[i] = 1;
            if ( hold1 ) b_tot[i] = 0;
        }
        if ( b1[i] == 1 && b2[i] == 0){
            b_tot[i] = 1;
            if ( hold1 ) b_tot[i] = 0;
        }
        if ( b1[i] == 1 && b2[i] == 1){
            b_tot[i] = 0;
            if ( hold1 ) {
                b_tot[i] = 1;
                continue;
            }
            hold1 = 1;
        }
        counter++;
        if ( counter == MAX+1 )break;
    }
    if(counter == MAX+1 )return -1;
    else{
        b_tot[ i-1 ] = -1;
        return 1;
    }


}


int bin2dec(int b[]){
    int i = 0, add = 0, temp = 0, power = 0;
    for( i = MAX ; i >= 0 ; i--){
        temp = b[i] * pow(2, power);
        add = add + temp;
        power++;
        if ( b[i] == -1)break;
    }
    return add;
}


int main()
{
    int i = 1, var1, var2, b1[MAX], b2[MAX], b_tot[MAX], x=0, y=0 ;




    while ( i != 0){


        var1 = input_dec();
        if( var1 < 0)printf("%d\n", var1);
        var2 = input_dec();
        if( var2 < 0)printf("%d\n", var2);
        dec2bin(var1, b1[MAX]);
        dec2bin(var2, b2[MAX]);
        printf("\nThe 2 binary numbers are: " );
        print_bin(b1[MAX]);
        printf("\t");
        print_bin(b2[MAX]);
        add_bin(b1[MAX], b2[MAX], b_tot[MAX]);
        printf("\nThe Add of the 2 numbers is in binary form: " );
        print_bin(b_tot[MAX]);
        printf("\tand in decimal form is: " );
        bin2dec(b_tot[MAX]);
        print_bin(b_tot[MAX]);


        printf("\nDo you want to play again?IF Yes type 1, IF No type 0:");
        scanf("%d", &i);
    }




    return 0;
}

for example if I put as input two 5,the program crashes