base conversion

[crackers8838]

Hi,
I was wondering is anyone could tell me how or give me pointers on how to convert the base of a number to another base. For example 2010 base 3 to base 4. I am stumped and I would appreciate any help I could get.

[TylerSBreton]

I dont think java provides any convienient way of doing this, you'll probably need to do it out longhand with loops and the % operator.

[crackers8838]

Ok, thanks. That is what I thought. I was hoping there was an easier way to do it.

[javabru]

Hi, I was wondering is anyone could tell me how or give me pointers on how to convert the base of a number to another base. For example 2010 base 3 to base 4. I am stumped and I would appreciate any help I could get.

I'm no expert, but you can do something like this:

public class Base3ToBase4 {

    public static void main(String[] args) {
        Base3ToBase4 tester = new Base3ToBase4();
        tester.test();
    }

    public void test() {
        long num3 = Long.parseLong("2010", 3);
        prt("num3 has a value of " + num3);

        String num3StrAsBase3 = Long.toString(num3, 3);
        prt("num3 as a String in Base 3 = " + num3StrAsBase3);

        String num3StrAsBase10 = Long.toString(num3, 10);
        prt("num3 as a String in Base 10 = " + num3StrAsBase10);

        String num3StrAsBase4 = Long.toString(num3, 4);
        prt("num3 as a String in Base 4 = " + num3StrAsBase4);
        prt("  *----------*");

        long num4 = Long.parseLong(num3StrAsBase4, 4);
        prt("num4 has a value of " + num4);
        
        String num4StrAsBase10 = Long.toString(num3, 10);
        prt("num4 as a String in Base 10 = " + num4StrAsBase10);

        String num4StrAsBase4 = Long.toString(num4, 4);
        prt("num4 as a String in Base 4 = " + num4StrAsBase4);

    }
    private void prt(String str) {
        System.out.println(str);
    }
}

The thing is, that the Long class keeps the same number, no matter what base it is in. Using the Long.toString(long num, int radix) method you can look at a String representation of the number in the base of your choice, and using Long.parseLong(String num, int radix) you can turn any String that validly represents a number in the associated base, into a long.

- Mike Bruton