Base 10 to base 2,8,16 conversion in java [duplicate]

Question

This question already has an answer here:

• In Java how do you convert a decimal number to base 36? 10 answers

I'm in this Object Oriented class, but I just don't know how to do this. I know basic fundamentals but nothing like this. I am asked to create a program that converts #'s base 10 to base 2, base 8,and base 16. Then, after we are asked to convert it back from 2,8,16 to base 10. I have gathered some information from other websites and I actually ended up editing a bit of it. Please help! I would prefer it if you guys actually helped and edited yourselves and sent it to me, but if that is too much to ask, please try to guide me through it as I do not know much of Java. So far I have:

import java.util.Scanner;

public class baseconverterr
{

public static void main(String[] args) {

      // Read the conversion choice from the user

      System.out.println("Choose 1 or 2 or 3:");

      System.out.println("1: conversion from base 10 to base 2 ");

      System.out.println("2: conversion from base 10 to base 8");

      System.out.println("3: conversion from base 10 to base 16");
      // do you want 1, 2 , or 3? you have your choice
      Scanner in = new Scanner(System.in);

      int choice = in.nextInt();

      String string = in.nextLine();

      // Read in the number to be converted and do the conversion

      String output= "";

      System.out.println("Please enter the number to be converted:");

      int input = in.nextInt();

      if (choice == 1)
      // if the user chooses choice #1, it will convert from base 10 to base 2
          output = Integer.toString(input, 2);

      else if (choice == 2)

          output = Integer.toString(input, 8);

    // if the user chooses choice #2, it will convert from base 10 to base of 8 
     else if (choice == 3)

          output = Integer.toString(input, 16);
   // if the user chooses choice #3, it will convert from base 10 to base 16
  else

      System.out.println("invalid entry");
      // everything else, it is invalid
      System.out.println("final output=" + output);
      // this prints the final output.

Answer 1

for a decimal x (base 10) you can use respectively for binary, octal, hex conversion

Integer.toString(x, 2),

Integer.toString(x, 8)

Integer.toString(x, 16).

then to convert it back to decimal, respectively from binary, octal, hex conversion

Integer.valueOf(binary_value, 2)

Integer.valueOf(octal_value, 8)

Integer.valueOf(hex_value, 16)

in your code, change the following:

output = Integer.toString(input, 16) //replace 16 for hex, 8 for octal, 2 for binary 

Answer 2

use this

    if (choice == 1)

          output = Integer.toString(input, 2);

      else if (choice == 2)

          output = Integer.toString(input, 8);

    // if the user chooses choice #2, it will convert from base 10 to base of 8 
     else if (choice == 3)

          output = Integer.toString(input, 16);

  else

      System.out.println("invalid entry");