Why does my program keep returning not a binary number?

Question

So the program is supposed to convert a binary number to a decimal number, by first checking if it is a binary number and then converting. No matter what input I give, it always says that the input is not a binary number and I can't figure out why. Here is my code.

public class Conversion {
    public static void main (String []args){
        String binaryNumber = args[0];
        if (checkBinary(binaryNumber)){
            int decimalNumber = binaryToDecimal(binaryNumber);
            System.out.print("The binary number " + binaryNumber + "is " + decimalNumber + "in base 10." );
        }
        else {
            System.out.println("The input is not binary!");
        }
    }

    public static boolean checkBinary(String binaryNumber){
        for (int i=0; i < binaryNumber.length(); i++) {
            char x = binaryNumber.charAt(i);
            if (x != '0' && x != '1'){
                return false;
            }
        }
        return true;
    }

    public static int binaryToDecimal(String binaryNumber) {
        int z = 1;
        int y = 0;
        for (int i = binaryNumber.length()- 1; i >= 0; i--){
            if (binaryNumber.charAt(i)=='1'){
                y += z;
            }
            z *= 2;
        }
        return y;
    }
}

Oddly the program as posted works for me. You might want to format your output a little. but I got the right answer: The binary number 101is 5in base 10. — Gavin
– Gavin, Commented Feb 20, 2016 at 18:40
Not directly to your question, but why not use Integer.parseInt(String, int) where the second argument is a radix (say 2). — Elliott Frisch
– Elliott Frisch, Commented Feb 20, 2016 at 18:45
You could add the input string to the error message "The input is not a binary," to verify that args[0] what you entered. — BryanT
– BryanT, Commented Feb 20, 2016 at 19:08

ernestk · Accepted Answer · 2016-02-20 19:23:30Z

1

you just need to edit if (x != '0' && x != '1') to if (x != '0' || x != '1')

answered Feb 20, 2016 at 19:23

ernestk

727 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Stefano Castagnino · Accepted Answer · 2016-02-20 20:43:35Z

Your class has this output, thats way thast run properly Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0 at Conversion.main(Conversion.java:10) To avoid this kind the problems id much better use Scanne, so i just replace :

`String binaryNumber = args[0]; `

for

`    

 Scanner input = new Scanner(System.in);
 System.out.println("Enter Binary: ");
  String binaryNumber = input.next();`

The whole code is bellow and run well(Java 8):

import java.util.Scanner;

public class Conversion {

    public static void main (String args[]){    
       // replace :String binaryNumber = args[0];
        Scanner input = new Scanner(System.in);
        System.out.println("Enter Binary: ");
        String binaryNumber = input.next();

        if (checkBinary(binaryNumber)){
            int decimalNumber = binaryToDecimal(binaryNumber);
            System.out.print("The binary number " + binaryNumber + " is " + decimalNumber + " in base 10." );
        }
        else {
            System.out.println("The input is not binary!");
        }
        input.close();
    }
    public static boolean checkBinary(String binaryNumber){
        for (int i=0; i = 0; i--){
            if (binaryNumber.charAt(i)=='1'){
                y += z;
            }
            z *= 2;
        }
        return y;
    }


}

OUTPUT : Enter Binary: 01000100111 The binary number 01000100111 is 551 in base 10.

Collectives™ on Stack Overflow

Why does my program keep returning not a binary number?

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related