CODEWITHSUNDEEP
java
user3157882
user3157882

Reputation: 21

Add zeros at the begining of a 32 -bit binary number.

I have a program that transforms decimal number into a binary number. I want the binary representation to have 32 digits, so I often need to add 0 at the beginning of the binary representation. How can I achieve it?

Example: 

 decimal: 
   9999999
 binary:
   00000000  01001100  01001011  00111111

This is the code I already have: Code:

class Binaer    {

    public static void main(String [] args) {
        java.util.Scanner scanner = new java.util.Scanner(System.in);

        long a = scanner.nextLong();

        while ( a != 0) {
            System.out.println(Integer.toBinaryString(a));
        }
    }
}

Upvotes: 0

Views: 1112

Answers (3)

3yakuya
3yakuya

Reputation: 2672

First, if you use Integer.toBinaryString(a), then a must be an Integer. Then, you can pad the received String using String.format:

number = Integer.toBinaryString(a);
paddedNumber = String.format("%32s", number).replace(' ', 0);

format will ensure paddedNumber has 32 signs by adding spaces at the beginning, if necessary. Then replace will replace spaces with '0' signs.

Upvotes: 0

Boris the Spider
Boris the Spider

Reputation: 61158

Easy, simply use String.format:

public static void main(String[] args) throws InterruptedException {
    final int i = 7;
    final String s = String.format("%32s", Integer.toBinaryString(i)).replace(' ', '0');
    System.out.println(s);
}

The first bit - String.format("%32s", Integer.toBinaryString(i)) - formats the int as a binary String which is padded from the start to 32 characters. The second bit - replace(' ', '0') - replaces the leading spaces with zeros.

Upvotes: 2

user2336315
user2336315

Reputation: 16067

You can use String.format or a StringBuilder :

java.util.Scanner scanner = new java.util.Scanner(System.in);
int a = scanner.nextInt();
StringBuilder sb = new StringBuilder();
for(int i = 0; i < Integer.numberOfLeadingZeros(a); i++)
    sb.append('0');
sb.append(Integer.toBinaryString(a));
System.out.println(sb.toString());

Upvotes: 0

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