import java.util.Scanner;
public class test {
    // 将字符串转换为十进制
    public static int toDecimal(String value, int base) {
        return Integer.parseInt(value, base);
    }

    // 将十进制转换为指定进制
    public static String fromDecimal(int value, int base) {
        return Integer.toString(value, base).toUpperCase();
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.println("请选择转换类型：");
        System.out.println("1. 二进制");
        System.out.println("2. 八进制");
        System.out.println("3. 十进制");
        System.out.println("4. 十六进制");
        System.out.print("请输入源进制（1-4）: ");
        int sourceBase = scanner.nextInt();

        System.out.print("请输入目标进制（1-4）: ");
        int targetBase = scanner.nextInt();

        System.out.print("请输入要转换的数字: ");
        String value = scanner.next();

        int decimalValue;

        // 将输入的值转换为十进制
        switch (sourceBase) {
            case 1:
                decimalValue = toDecimal(value, 2);
                break;
            case 2:
                decimalValue = toDecimal(value, 8);
                break;
            case 3:
                decimalValue = toDecimal(value, 10);
                break;
            case 4:
                decimalValue = toDecimal(value, 16);
                break;
            default:
                throw new IllegalArgumentException("无效的源进制");
        }

        // 将十进制值转换为目标进制
        String result;
        switch (targetBase) {
            case 1:
                result = fromDecimal(decimalValue, 2);
                break;
            case 2:
                result = fromDecimal(decimalValue, 8);
                break;
            case 3:
                result = fromDecimal(decimalValue, 10);
                break;
            case 4:
                result = fromDecimal(decimalValue, 16);
                break;
            default:
                throw new IllegalArgumentException("无效的目标进制");
        }

        System.out.println("转换结果: " + result);
        scanner.close();
    }
}