TheAlgorithms · varunu28 · Aug 25, 2018 · Aug 25, 2018 · Aug 25, 2018
diff --git a/src/main/com/java/conversions/AnyBaseToDecimal.java b/src/main/com/java/conversions/AnyBaseToDecimal.java
@@ -0,0 +1,39 @@
+package src.main.com.java.conversions;
+
+public class AnyBaseToDecimal {
+    /**
+     * This method produces a decimal value of any given input number of any base
+     * @param inpNum String of which we need the decimal value and base in integer format
+     * @return string format of the decimal value
+     */
+
+    public String convertToDecimal(String inpNum, int base) {
+        int len = inpNum.length();
+        int num = 0;
+        int pow = 1;
+
+        for (int i=len-1; i>=0; i--) {
+            if (valOfChar(inpNum.charAt(i)) >= base) {
+                return "Invalid Number";
+            }
+            num += valOfChar(inpNum.charAt(i))*pow;
+            pow *= base;
+        }
+        return String.valueOf(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
+     */
+
+    private static int valOfChar(char c) {
+        if (c >= '0' && c <= '9') {
+            return (int)c - '0';
+        }
+        else {
+            return (int)c - 'A' + 10;
+        }
+    }
+}
diff --git a/src/test/com/java/conversions/AnyBaseToDecimalTest.java b/src/test/com/java/conversions/AnyBaseToDecimalTest.java
@@ -0,0 +1,39 @@
+package src.test.com.java.conversions;
+
+import org.junit.Assert;
+import org.junit.Test;
+import src.main.com.java.conversions.AnyBaseToDecimal;
+
+public class AnyBaseToDecimalTest {
+
+  @Test
+  public void testAnyBaseToDecimal() {
+    AnyBaseToDecimal anyBaseToDecimal = new AnyBaseToDecimal();
+    Assert.assertEquals("Invalid Number", anyBaseToDecimal.convertToDecimal("2", 2));
+    Assert.assertEquals("Invalid Number", anyBaseToDecimal.convertToDecimal("3", 2));
+    Assert.assertEquals("3", anyBaseToDecimal.convertToDecimal("11", 2));
+    Assert.assertEquals("4", anyBaseToDecimal.convertToDecimal("100", 2));
+    Assert.assertEquals("5", anyBaseToDecimal.convertToDecimal("101", 2));
+    Assert.assertEquals("10", anyBaseToDecimal.convertToDecimal("1010", 2));
+    Assert.assertEquals("1024", anyBaseToDecimal.convertToDecimal("10000000000", 2));
+
+    Assert.assertEquals("Invalid Number", anyBaseToDecimal.convertToDecimal("8", 8));
+    Assert.assertEquals("Invalid Number", anyBaseToDecimal.convertToDecimal("9", 8));
+    Assert.assertEquals("7", anyBaseToDecimal.convertToDecimal("7", 8));
+    Assert.assertEquals("8", anyBaseToDecimal.convertToDecimal("10", 8));
+    Assert.assertEquals("9", anyBaseToDecimal.convertToDecimal("11", 8));
+    Assert.assertEquals("10", anyBaseToDecimal.convertToDecimal("12", 8));
+    Assert.assertEquals("1024", anyBaseToDecimal.convertToDecimal("2000", 8));
+
+    Assert.assertEquals("Invalid Number", anyBaseToDecimal.convertToDecimal("A", 10));
+    Assert.assertEquals("10", anyBaseToDecimal.convertToDecimal("10", 10));
+    Assert.assertEquals("1024", anyBaseToDecimal.convertToDecimal("1024", 10));
+
+    Assert.assertEquals("Invalid Number", anyBaseToDecimal.convertToDecimal("G", 16));
+    Assert.assertEquals("16", anyBaseToDecimal.convertToDecimal("10", 16));
+    Assert.assertEquals("17", anyBaseToDecimal.convertToDecimal("11", 16));
+    Assert.assertEquals("100", anyBaseToDecimal.convertToDecimal("64", 16));
+    Assert.assertEquals("225", anyBaseToDecimal.convertToDecimal("E1", 16));
+    Assert.assertEquals("1024", anyBaseToDecimal.convertToDecimal("400", 16));
+  }
+}