Scenario

In aviation, the aircraft's transponders transmit a code so that they can identify one another. This code uses the octal system, a number system which has a base of 8. We have been asked to write a method to convert octal numbers into decimals. For example, the octal number 17 is represented as 15 in the decimal system.

Aim

To be able to adapt the algorithm shown in the previous section to be used in a different scenario.

Prerequisites

• Ensure that you have a class available on the following path:

https://github.com/TrainingByPackt/Data-Structures-and-Algorithms-in-Java/blob/master/src/main/java/com/packt/datastructuresandalg/lesson1/activity/octaltodecimal/OctalToDecimal.java

• You will find the following method that needs implementing:

 public int convertToDecimal (String octal) 

• If you have your project set up, you can run the unit test for this activity by running the following command: 

gradlew test --tests com.packt.datastructuresandalg.
lesson1.activity.octaltodecimal* 

Steps for Completion

1. The algorithms shown in Snippet 1.1 the preceding snippets of code can be adapted to work with octal numbers instead of binary.
2. Change the base from two to eight. This can be done by changing the conversion multiplier variable in Snippet 1.1.
3. Parse the digit being processed to convert it into an integer. This integer can then be multiplied by the conversion variable or result of the power function.

In this first section, we introduced the idea of algorithms by working on a simple example. It's important to note that for every problem multiple solutions exist. Choosing the right algorithm to solve your problem will depend on several metrics, such as performance and memory requirements.