package Conversions;
import java.util.Arrays;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.Scanner;
/**
* Class for converting from "any" base to "any" other base, when "any" means from 2-36. Works by
* going from base 1 to decimal to base 2. Includes auxiliary method for determining whether a
* number is valid for a given base.
*
* @author Michael Rolland
* @version 2017.10.10
*/
public class AnyBaseToAnyBase {
/** Smallest and largest base you want to accept as valid input */
static final int MINIMUM_BASE = 2;
static final int MAXIMUM_BASE = 36;
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
String n;
int b1, b2;
while (true) {
try {
System.out.print("Enter number: ");
n = in.next();
System.out.print(
"Enter beginning base (between " + MINIMUM_BASE + " and " + MAXIMUM_BASE + "): ");
b1 = in.nextInt();
if (b1 > MAXIMUM_BASE || b1 < MINIMUM_BASE) {
System.out.println("Invalid base!");
continue;
}
if (!validForBase(n, b1)) {
System.out.println("The number is invalid for this base!");
continue;
}
System.out.print(
"Enter end base (between " + MINIMUM_BASE + " and " + MAXIMUM_BASE + "): ");
b2 = in.nextInt();
if (b2 > MAXIMUM_BASE || b2 < MINIMUM_BASE) {
System.out.println("Invalid base!");
continue;
}
break;
} catch (InputMismatchException e) {
System.out.println("Invalid input.");
in.next();
}
}
System.out.println(base2base(n, b1, b2));
in.close();
}
/** Checks if a number (as a String) is valid for a given base. */
public static boolean validForBase(String n, int base) {
char[] validDigits = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I',
'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
};
// digitsForBase contains all the valid digits for the base given
char[] digitsForBase = Arrays.copyOfRange(validDigits, 0, base);
// Convert character array into set for convenience of contains() method
HashSet