## The challenge

Write a function that converts an input string contains a `hex` value, and return a `decimal`.

## Test cases

 `````` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 `````` ``````import org.junit.Test; import static org.junit.Assert.*; public class ExampleTests { @Test public void examples() { // assertEquals("expected", "actual"); assertEquals(1, ConvertHexToDec.hexToDec("1")); assertEquals(10, ConvertHexToDec.hexToDec("a")); assertEquals(16, ConvertHexToDec.hexToDec("10")); assertEquals(255, ConvertHexToDec.hexToDec("FF")); assertEquals(-12, ConvertHexToDec.hexToDec("-C")); } } ``````

## The solution in Java

In Java, it is really easy to convert Hex to Decimal.

You simply use the `Integer` class and call the `parseInt` method, making sure to also provide the base that you want to convert from.

As we know that the input will be a hex value, and we also know that the hexadecimal number system is a base 16 numbering system, we are able to do the following:

 ``````1 2 3 4 5 6 7 `````` ``````public class ConvertHexToDec { public static int hexToDec(final String hexString) { return Integer.parseInt(hexString, 16); } } ``````