computer science: a structured programming approach using c1 4-6 scope scope determines the region...

Computer Science: A Structured Programming Approach Using C 1

4-6 Scope

Scope determines the region of the program in which a Scope determines the region of the program in which a defined object is visible. Scope pertains to any object defined object is visible. Scope pertains to any object that can be declared, such as a variable orthat can be declared, such as a variable ora function declaration. a function declaration.

Global ScopeLocal Scope

Topics discussed in this section:Topics discussed in this section:


FIGURE 4-32 Scope for Global and Block Areas


Variables are in scope from declaration until the end of their block.

NoteNote


It is poor programming style to reuse identifiers within the same scope.

NoteNote


4-7 Programming Example— Incremental Development

Top–down development, a concept inherent to Top–down development, a concept inherent to modular programming, allows us to develop programs modular programming, allows us to develop programs incrementally. By writing and debugging each incrementally. By writing and debugging each function separately, we are able to solve the program function separately, we are able to solve the program in smaller steps, making the whole process easier.in smaller steps, making the whole process easier.

First Increment: main and getDataSecond Increment: addFinal Increment: Print ResultsThe



FIGURE 4-33 Calculator Program Design


PROGRAM 4-13 Calculator Program—First Increment


PROGRAM 4-14 Calculator Program—Second Increment


PROGRAM 4-15 Calculator Program—Final Increment


4-8 Software Engineering

In this section we discuss three different but related In this section we discuss three different but related aspects of software engineering design: the structure aspects of software engineering design: the structure chart, functional cohesion, and top–down development.chart, functional cohesion, and top–down development.

Structure ChartsStructure Chart RulesFunctional CohesionTop–Down Development



FIGURE 4-34 Structure Chart Symbols


FIGURE 4-35 Structure Chart Design


Structure charts show only function flow; they contain no code.

NoteNote


FIGURE 4-36 Common Functions in a Structure Chart


Table 4-1 Structure Chart Rules


FIGURE 4-37 Calculate Taxes Design


FIGURE 4-38 Design For Print Report


PROGRAM 4-16 Top–down Development Example

computer science: a structured programming approach using c1 4-6 scope scope determines the region...

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modular programming

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poor programming style

block areascomputer

addfinal increment

getdatasecond increment

function flow

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