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Foreshadow arrays right after teaching for loops by showing students how to create a 1x6 grid using the rectangle object in the Java objectdraw library because visualizations built off of recently introduced material provide a useful transition.
- Before demonstrating, ask students to try creating a 1x6 grid of rectangle objects to students.
- The goal is to give students a chance practice their problem solving and programming skills before scaffolding them through the process.
- Demo how to draw 6 overlapping rectangles by repeatedly drawing a rectangle in the same spot.
- Now, show students how to shift the x position of each rectangle so they draw rectangles one after the other on the screen.
- Finally, it’s time to foreshadow arrays.
- Explain that you can’t access the rectangles after you create them.
- Even if you make a global variable outside the loop for the rectangles you will only ever have access to the last rectangle created.
- Introduce arrays as a structure and draw parallels, like the fact above, to the shapes they just drew.
- For more information on this activity, check out the worksheet McAvoy uses for this activity.