Add HexadecimalToDecimal conversion

MohamedBechir · MohamedBechir · commit ccf506514a6b · 2020-05-25T02:24:06.000+01:00
diff --git a/src/main/java/com/conversions/HexadecimalToDecimal.java b/src/main/java/com/conversions/HexadecimalToDecimal.java
@@ -0,0 +1,37 @@
+package com.conversions;
+
+
+public class HexadecimalToDecimal {
+
+	/**
+     * This method converts a Hexadecimal number to a decimal  number
+     *
+     * @param hexadecimalStr
+     * @return decimal number
+     */
+	 public String hexToDecimal(String hexaStr) {
+		 String hexaNumbers = "0123456789ABCDEF";
+		 int m, result = 0;
+		 char letter;
+		 String decimalStr;
+		 hexaStr = hexaStr.toUpperCase();
+		 
+		 for (int i = 0 ; i < hexaStr.length() ; i++) {
+				 /**
+				  * Letter will store the hexadecimal number as long as we loop through
+				  * the string
+				  */
+				 letter = hexaStr.charAt(i);
+
+				 /**
+				  * m is the index of the number that we are looping through in the
+				  * hexaNumbers
+				  */
+				 m = hexaNumbers.indexOf(letter);
+				 result = 16*result + m;
+			 }
+			
+		  decimalStr = String.valueOf(result);
+		 return decimalStr ;
+	    }
+}
diff --git a/src/test/java/com/conversions/HexadecimalToDecimalTest.java b/src/test/java/com/conversions/HexadecimalToDecimalTest.java
@@ -0,0 +1,23 @@
+package com.conversions;
+
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+class HexadecimalToDecimalTest {
+
+	@Test
+	void testHexadecimalToDecimalTest() {
+
+		HexadecimalToDecimal hexadecimalToDecimal = new HexadecimalToDecimal();
+        Assertions.assertEquals("171", hexadecimalToDecimal.hexToDecimal("AB"), "Incorrect Conversion");
+        Assertions.assertEquals("5680077", hexadecimalToDecimal.hexToDecimal("56ABCD"), "Incorrect Conversion");
+        Assertions.assertEquals("5174921", hexadecimalToDecimal.hexToDecimal("4ef689"), "Incorrect Conversion");
+        Assertions.assertEquals("1263", hexadecimalToDecimal.hexToDecimal("4EF"), "Incorrect Conversion");
+        Assertions.assertEquals("11259375", hexadecimalToDecimal.hexToDecimal("ABCDEF"), "Incorrect Conversion");
+        //It returns -1 if you enter a wrong hexaDecimal
+        Assertions.assertEquals("-1", hexadecimalToDecimal.hexToDecimal("K"), "Incorrect Conversion");
+        
+	}
+
+}
