Robot Directions & Sequencing

An algorithm is a sequence of steps that solves a problem. Every program you have ever used runs on algorithms.

When you build a command sequence to move the robot, you are writing an algorithm. The robot follows each step exactly as written.

• Step 1 runs before Step 2
• Every step must be clear and specific
• The robot does not guess or improvise

The same set of commands in a different order produces a completely different result. Try it with the robot.

"Forward, Turn Right, Forward" takes you somewhere different than "Turn Right, Forward, Forward." This is why programmers must think carefully about sequence.

• Swapping two steps can change the entire outcome
• Order is one of the three core ideas in programming (along with loops and decisions)

When a program does the wrong thing, programmers debug it by reading the steps one at a time to find the mistake.

If your robot does not reach the star, go through your sequence step by step. Ask: "After Step 1, where is the robot? After Step 2?"

• Use the "Step" button in Learn mode to trace step by step
• Look for the first command that gives an unexpected result
• Fix that command and re-run

Every app, game, and website you use runs step-by-step instructions like the ones you are building here. Computers are very fast at following these steps, but they follow them one at a time.

• A game character moves based on a sequence of physics steps
• A search engine follows steps to rank results
• Your phone alarm follows steps to check the time and ring
• Robots in factories follow motion programs just like this grid robot