How to convert Decimal number to Octal number in Java?

Problem Description :

Write a program in Java that converts Decimal number to Octal number.

Decimal to Octal conversion

Concept :

Click here to learn how to convert Decimal number to Octal number Mathematically. We are using Method 2 : Converting with Remainders.

Recommended :

Learn different methods of reversing a String, using.

• Library method of StringBuilder class.
• Iteration
• Recursion

Java Program :

	package com.javamultiplex.baseconversion;
	import java.util.Scanner;
	/**
	*
	* @author Rohit Agarwal
	* @category Base Conversion
	* @problem Convert Decimal to Octal
	*
	*/
	public class DecimalToOctal {
	public static void main(String[] args) {
	Scanner input = null;
	try {
	input = new Scanner(System.in);
	System.out.println("Enter decimal number : ");
	String number = input.next();
	if (isDecimalNumber(number)) {
	String octal = getOctalNumber(number);
	System.out.println("Octal number : " + octal);
	} else {
	System.out.println("Please enter valid decimal number.");
	}
	} finally {
	if (input != null) {
	input.close();
	}
	}
	}
	private static String getOctalNumber(String number) {
	// Converting String to Integer.
	int decimal = Integer.parseInt(number);
	int remainder = 0;
	StringBuilder octal = new StringBuilder();
	while (decimal != 0) {
	remainder = decimal % 8;
	// Converting Integer to String and adding into StringBuilder.
	octal.append(String.valueOf(remainder));
	decimal = decimal / 8;
	}
	// Reverse String using library function of StringBuilder class.
	return octal.reverse().toString();
	}
	private static boolean isDecimalNumber(String number) {
	// Regular expression that matches String containing only digits [0-9].
	String pattern = "^[0-9]+$";
	boolean result = false;
	if (number.matches(pattern)) {
	result = true;
	}
	return result;
	}
	}

view raw DecimalToOctal.java hosted with ❤ by GitHub

Output :

Output - How to convert Decimal number to Octal number in Java?

References :

https://en.wikipedia.org/wiki/Regular_expression

http://docs.oracle.com/javase/7/docs/api/java/lang/String.html

https://docs.oracle.com/javase/7/docs/api/java/lang/StringBuilder.html

https://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html

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Tags : Conversion problems, Decimal to Octal, Solution in Java, String, StringBuilder, Regular expressions, if else statement.

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