A Job to Do

Overview

You have learned a lot about programming Guido. Congratulations! What you may not realize is that you have learned a lot about programming in any language. Most programs are a sequence of steps, interspersed with conditional decisions and groups of instructions that repeat. All of the projects have been successively more complex.

Implementing the solutions to the assignments so far has required a little more thought at each step. You understand the question and the desired result, but it's not immediately clear sometimes how to get it done. You should have realized that the way you would do it if you were Guido is often the way Guido would do it, using the instructions available.

Often, then, it's best to figure out how you would accomplish a task. Write the steps down in your own words with pencil and paper. This is sometimes called pseudocode because it isn't really instructions that Guido could use. But it helps you understand what needs to happen. Then you code it -- write the real instructions -- to create a GvR program.

Be sure to think this assignment through before you start coding. First figure out the algorithm, or sequence of steps, required. Then, looking at the sample world, simulate in your mind the execution of the program you are going to write. If it does what you expect, then and only then should you start coding.

Project

Guido's Dad is a farmer. When Guido is not doing his homework, he helps in the field. Today he has to harvest the crop. The field always has 6 rows and 6 columns, but the crop did not grow in all the locations, as shown. Create a world with a mostly populated 6x6 field in the middle as shown.

Harvest the crop using a nested do statement - one or more do statements within a do statement - to perform the harvesting operation. In pseudocode, this would be something like:

do six times 
    go across, harvesting beepers
    go back to left edge
    go up one
stop

but the "go across, harvesting beepers" is a do loop itself:

do six times 
    do six times
        go one to the right
        harvest if possible
        go back to left edge
        go up one
stop

Note that pseudocode is not GvR code but a more English-like description of the algorithm in code-like structure. Once the pseudocode is written, turn it into GvR code and execute it to complete this assignment.

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Copyright © 2003 Roger Frank.