4.3 Pseudocode

Pseudocode is an informal language that helps you develop algorithms without having to worry about the strict details of C++ language syntax. The pseudocode we present is particularly useful for developing algorithms that will be converted to structured portions of C++ programs. Pseudocode is similar to everyday English—it’s convenient and user friendly, but it’s not an actual computer programming language. You’ll see an algorithm written in pseudocode in Fig. 4.1. You may, of course, use your own native language(s) to develop your own pseudocode style.

Pseudocode does not execute on computers. Rather, it helps you “think out” a program before attempting to write it in a programming language, such as C++. This chapter provides several examples of using pseudocode to develop C++ programs.

The style of pseudocode we present consists purely of characters, so you can type pseudocode conveniently, using any text-editor program. A carefully prepared pseudocode program can easily be converted to a corresponding C++ program.

Pseudocode normally describes only statements representing the actions that occur after you convert a program from pseudocode to C++ and the program is run on a computer. Such actions might include input, output, assignments or calculations. In our pseudocode, we typically do not include variable declarations, but some programmers choose to list variables and mention their purposes.

Addition Program Pseudocode

Let’s look at an example of pseudocode that may be written to help a programmer create the addition program of Fig. 2.5. This pseudocode (Fig. 4.1) corresponds to the algorithm that inputs two integers from the user, adds these integers and displays their sum. We show the complete pseudocode listing here—we’ll show how to create pseudocode from a problem statement later in the chapter.

Notice that the pseudocode statements are simply English statements that convey what task is to be performed in C++. Lines 1–2 correspond to the C++ statements in lines

Fig. 4.1 Pseudocode for the addition program of Fig. 2.5.

Alternate View 

 1   Prompt the user to enter the first integer
 2   Input the first integer
 3
 4   Prompt the user to enter the second integer
 5   Input the second integer
 6
 7   Add first integer and second integer, store result
 8   Display result

13–14 of Fig. 2.5. Lines 4–5 correspond to the statements in lines 16–17 and lines 7–8 correspond to the statements in lines 19 and 21.

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