Finding and Fixing Errors in Algorithms

Making mistakes while writing an algorithm is normal, and even experienced programmers do it. The executor carries out commands exactly and without thinking, so it will not fix a mistake by itself. Being able to notice and find an error is an important skill for a programmer.

There are two kinds of errors. A syntax error means a command is written incorrectly, or the executor does not know that command. A logic error means the commands are written correctly, but their order or number is wrong, so the result is not what was expected. For example, moving a robot 4 squares instead of 3 or forgetting a turn is a logic error.

The best way to find an error is to test the algorithm by hand. You pick a simple example and carry out the algorithm command by command, writing the values of the variables in a table after each step. The step where the result differs from the expected one points to the error.

Once you have found an error, fix it and test the algorithm again. It is better to fix only one error at a time, so you can see how the change affected the result. Finding errors is part of learning, so do not be upset by them.

Key takeaways

• The executor follows commands without thinking and will not fix errors itself.
• Errors are either syntax errors or logic errors.
• Testing an algorithm by hand helps find errors.
• Fix errors one at a time and test again each time.