Base 10 to base 2,8,16 conversion in java

Question

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.

There's a nice trick that working right to left, the remainder of dividing the number by the new base will be the next digit, with the original dividing by the new base every time. It's pretty handy when you don't want to write a new function for each new base. — chris, Apr 15 '13 at 06:13

Ankit · Answer 1 · 2013-04-15T07:04:22.447

32

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

edited Apr 15 '13 at 07:04

answered Apr 15 '13 at 06:14

Ankit

6,554
6
49
71

1

what do i have to change? I don't understand. i'm a complete noob at this... – Justin Park Apr 15 '13 at 06:17
I figured it out. I tried to run the program, but after I select a number, i.e.: 1, which is the base 10 to base 2 converter. but when i put in the number to be converted, it just tells me it's invalid. (by my code) not an error – Justin Park Apr 15 '13 at 06:25
there is no error. when i run it and it says, " what number do you want to convert", and i enter a random number, there will be white space and nothign will come up. – Justin Park Apr 15 '13 at 06:33
Choose 1 or 2 or 3: 1: conversion from base 10 to base 2 2: conversion from base 10 to base 8 3: conversion from base 10 to base 16 2 Please enter the number to be converted: 10000 nothing comes up after 10000 – Justin Park Apr 15 '13 at 06:36
it will work, just make sure ur printing output, System.out.println("output=" + output); – Ankit Apr 15 '13 at 06:45
yeah got it. do you know how to conver tehm back? – Justin Park Apr 15 '13 at 06:49
use valueOf(String s, int radix) method – Ankit Apr 15 '13 at 06:52
could you instruct me how to use that method? – Justin Park Apr 15 '13 at 07:03
where do i put it in? – Justin Park Apr 15 '13 at 07:07
program is updated on top. – Justin Park Apr 15 '13 at 07:08
3

...and he fails his class because he was supposed to actually write the algorithm so he could learn something... :) – Stijn de Witt Aug 26 '13 at 18:06

score 0 · Answer 2 · answered Apr 15 '13 at 06:17

0

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");

answered Apr 15 '13 at 06:17

NPKR

5,368
4
31
48

where do i put this? in which class or method? update: i got it! it doesn't really work though... – Justin Park Apr 15 '13 at 06:18
remove your code after System.out.println("Please enter the number to be converted:"); int input = in.nextInt(); and add given code – NPKR Apr 15 '13 at 06:19
now, the i is "wrong" what do i do to stop the error? – Justin Park Apr 15 '13 at 06:20
check with latest code – NPKR Apr 15 '13 at 06:21
I figured it out. I tried to run the program, but after I select a number, i.e.: 1, which is the base 10 to base 2 converter. but when i put in the number to be converted, it just tells me it's invalid. (by my code) not an error – Justin Park Apr 15 '13 at 06:24
And so he has his first taste of the development world. Yep - it's time to google that up. It's time to google that other thing. DYWMTGTFY (Stands for "Do you want me to google that for you?". The meaning is that, in reality, you should probably google it up yourself first. – Rodney P. Barbati Nov 04 '16 at 00:49

Base 10 to base 2,8,16 conversion in java

2 Answers2

Linked