Question

I have a homework to do a decimal to binary conversation. This is the code I have:

int num = 0;
int temp = 0;

Scanner sc = new Scanner(System.in);
num = sc.nextInt();

//System.out.print(""+ num%2+ (num%2)%2);
while(num != 0) {
  temp = num;
  System.out.print(""+(int) temp % 2);
  num = num / 2;    
}

It is working fine, but it giving me the output as LSB and not as MSB.

For example:

35
110001

but I need it to be 100011.

I cannot use any function or method to reverse it. I know I can put it in an array, string or whatever and do some magic. But I can use only the while loop, modulo and print.

Any Suggestions?

Answer 1

Don’t output each digit as you find them. Build your output incrementally and then print it at the end.

public static void main(String[] args)
{
    int num = 0;
    int temp = 0;

    Scanner sc = new Scanner(System.in);
            num = sc.nextInt();

    int place = 1;
    int output = 0;

    while(num != 0) {
       temp = num % 2;
       num = num / 2;    

       output += (place*temp);
       place *=10;
    }

    System.out.print(""+output);
}   

You may need to modify this to handle large or negative numbers.