TheAlgorithms · yanglbme · Oct 28, 2019 · Oct 27, 2019 · Oct 27, 2019 · Oct 27, 2019
@@ -1,61 +1,53 @@
 package Conversions;
 
-import java.io.BufferedReader;
-import java.io.InputStreamReader;
-
 /**
- *
  * @author Varun Upadhyay (https://github.com/varunu28)
- *
  */
 
 // Driver program
 public class AnyBaseToDecimal {
-    public static void main (String[] args) throws Exception{
-        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
-
-        String inp = br.readLine();
-        int base =  Integer.parseInt(br.readLine());
-
-        System.out.println("Input in base " + base + " is: " + inp);
-        System.out.println("Decimal value of " + inp + " is: " + convertToDecimal(inp, base));
-
-        br.close();
+    public static void main(String[] args) {
+        assert convertToDecimal("1010", 2) == Integer.valueOf("1010", 2);
+        assert convertToDecimal("777", 8) == Integer.valueOf("777", 8);
+        assert convertToDecimal("999", 10) == Integer.valueOf("999", 10);
+        assert convertToDecimal("ABCDEF", 16) == Integer.valueOf("ABCDEF", 16);
+        assert convertToDecimal("XYZ", 36) == Integer.valueOf("XYZ", 36);
     }
 
     /**
-     * This method produces a decimal value of any given input number of any base
-     * @param inp_num String of which we need the decimal value and base in integer format
-     * @return string format of the decimal value
+     * Convert any radix to decimal number
+     *
+     * @param s     the string to be convert
+     * @param radix the radix
+     * @return decimal of bits
+     * @throws NumberFormatException if {@code bits} or {@code radix} is invalid
      */
-
-    public static String convertToDecimal(String inp_num, int base) {
-        int len = inp_num.length();
+    public static int convertToDecimal(String s, int radix) {
         int num = 0;
         int pow = 1;
 
-        for (int i=len-1; i>=0; i--) {
-            if (valOfChar(inp_num.charAt(i)) >= base) {
-                return "Invalid Number";
+        for (int i = s.length() - 1; i >= 0; i--) {
+            int digit = valOfChar(s.charAt(i));
+            if (digit >= radix) {
+                throw new NumberFormatException("For input string " + s);
             }
-            num += valOfChar(inp_num.charAt(i))*pow;
-            pow *= base;
+            num += valOfChar(s.charAt(i)) * pow;
+            pow *= radix;
         }
-        return String.valueOf(num);
+        return num;
     }
 
     /**
-     * This method produces integer value of the input character and returns it
-     * @param c Char of which we need the integer value of
-     * @return integer value of input char
+     * Convert character to integer
+     *
+     * @param c the character
+     * @return represented digit of given character
+     * @throws NumberFormatException if {@code ch} is not UpperCase or Digit character.
      */
-
     public static int valOfChar(char c) {
-        if (c >= '0' && c <= '9') {
-            return (int)c - '0';
-        }
-        else {
-            return (int)c - 'A' + 10;
+        if (!(Character.isUpperCase(c) || Character.isDigit(c))) {
+            throw new NumberFormatException("invalid character :" + c);
         }
+        return Character.isDigit(c) ? c - '0' : c - 'A' + 10;
     }
 }
@@ -106,7 +106,7 @@ public void deleteNth(int position) {
      * @throws IndexOutOfBoundsException if {@code position} not in range {@code low} to {@code high}
      */
     public void checkBounds(int position, int low, int high) {
-        if (position < low || position > high) {
+        if (position > high || position < low) {
             throw new IndexOutOfBoundsException(position + "");
         }
     }

@@ -62,7 +62,7 @@ public static boolean isBalanced(String brackets) {
                 case ')':
                 case ']':
                 case '}':
-                    if (!(!bracketsStack.isEmpty() && isPaired(bracketsStack.pop(), bracket))) {
+                    if (bracketsStack.isEmpty() || !isPaired(bracketsStack.pop(), bracket)) {
                         return false;
                     }
                     break;