ADD file via upload

Main.java

@@ -0,0 +1,81 @@
+import java.util.Scanner;
+
+public class Main {
+
+    // Helper function to convert a number from any base to decimal
+    public static long convertToDecimal(String number, int base) {
+        long result = 0;
+        int power = 0;
+
+        // Traverse the number from right to left
+        for (int i = number.length() - 1; i >= 0; i--) {
+            char digit = number.charAt(i);
+            int value = 0;
+
+            // Convert character to integer value
+            if (Character.isDigit(digit)) {
+                value = digit - '0';
+            } else {
+                value = Character.toUpperCase(digit) - 'A' + 10;
+            }
+
+            // Check if the value is within the allowed range for the given base
+            if (value >= base) {
+                throw new IllegalArgumentException("Invalid digit for the given base");
+            }
+
+            // Add the digit's value to the result
+            result += value * Math.pow(base, power);
+            power++;
+        }
+
+        return result;
+    }
+
+    // Helper function to convert a number from decimal to any base
+    public static String convertFromDecimal(long number, int base) {
+        if (number == 0) {
+            return "0";
+        }
+
+        StringBuilder result = new StringBuilder();
+        char[] digits = "0123456789ABCDEF".toCharArray();
+
+        while (number > 0) {
+            int remainder = (int) (number % base);
+            result.insert(0, digits[remainder]);
+            number /= base;
+        }
+
+        return result.toString();
+    }
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        // Input the number X in any base Rx
+        System.out.print("输入数字X: ");
+        String numberX = scanner.nextLine();
+        System.out.print("Enter the base Rx (2-16): ");
+        int baseX = scanner.nextInt();
+
+        // Input the target base Ry
+        System.out.print("Enter the target base Ry (2-16): ");
+        int baseY = scanner.nextInt();
+
+        try {
+            // Convert X to decimal
+            long decimalValue = convertToDecimal(numberX, baseX);
+
+            // Convert decimal to target base Y
+            String numberY = convertFromDecimal(decimalValue, baseY);
+
+            // Output the result
+            System.out.println("The number " + numberX + " in base " + baseX + " is " + numberY + " in base " + baseY);
+        } catch (IllegalArgumentException e) {
+            System.out.println(e.getMessage());
+        }
+
+        scanner.close();
+    }
+}