Numbers missing from stack and linkedlist JAVA?

Question

I am trying to implement code to convert decimal to binary with a certain precision, for that I use stack and linked list to add the non decimal and decimal parts calculated. I then use Stringbuilder to pop/poll element one by one to ge the final binary number. SOURCE : http://www.geeksforgeeks.org/convert-decimal-fraction-binary-number/

When I push the elements onto stack/list I see they are being pushed(Using o/p stmts for that). For some reason I dont see them when popping out the elements.

Here is my code

import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;

public class BinaryToDecimal {

public String toBinary(float n, int p){
    int non_dec = (int) Math.floor(n);
    Stack<Integer> s_non_dec = new Stack<>();
    LinkedList<Integer> q_dec = new LinkedList<>();
    float dec = n - non_dec;
    int quotient = 1;
    while(quotient > 0){
        quotient = non_dec/2;
        int remainder = non_dec%2;
        System.out.println("quotient"+quotient+"non_dec"+non_dec+"remainder"+remainder);
        s_non_dec.push(remainder);
        non_dec = quotient;
    }

    while(p>0){
        System.out.println("before dec"+dec);
        dec = dec*2;
        System.out.println("after dec"+dec);
        if(dec >=1){
            System.out.println("add 1");
            q_dec.add(1);
            dec = dec - 1;
        }
        else{
            System.out.println("add 0");
            q_dec.add(0);
        }
        p--;
    }
    StringBuilder sb = new StringBuilder();
    for(int i=0;i<s_non_dec.size();i++){
        System.out.println("pop"+s_non_dec.peek());
        sb.append(s_non_dec.pop());
    }
    sb.append('.');
    for(int i=0;i<q_dec.size();i++){
        System.out.println("poll"+q_dec.peek());
        sb.append(q_dec.poll());
    }

    return sb.toString();
}

public static void main (String args[]){
    BinaryToDecimal btd = new BinaryToDecimal();
    System.out.println(btd.toBinary(2.47f, 5));
}

}

My output :

quotient1non_dec2remainder0
quotient0non_dec1remainder1
before dec0.47000003
after dec0.94000006
add 0
before dec0.94000006
after dec1.8800001
add 1
before dec0.8800001
after dec1.7600002
add 1
before dec0.7600002
after dec1.5200005
add 1
before dec0.52000046
after dec1.0400009
add 1
pop1
poll0
poll1
poll1
1.011

as seen above, even tough I push 1 and 0 into my stack, my output has only 1 for the non decimal part instead of 1 and 0! The same happens for the decimal part! Ive been looking at this code for hours, any help is appreciated!

kunal shrivastava · Accepted Answer · 2017-04-18 12:16:45Z

1

Error is with your for loop.

for(int i=0;i<s_non_dec.size();i++){
    System.out.println("pop"+s_non_dec.peek());
    sb.append(s_non_dec.pop());
}

Here you are looping on stack size s_non_dec.size, which will keep on decreasing after every pop operation and "i" will keep on increasing after every iteration. You can better check if stack is empty or not. Use

while(!s_non_dec.isEmpty()) {
    System.out.println("pop"+s_non_dec.peek());
    sb.append(s_non_dec.pop());
}

answered Apr 18, 2017 at 12:16

kunal shrivastava

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