Sams Teach Yourself C in 21 Days

Summary ............................................................................................................

Today you covered some of the more advanced programming tools available with C

compilers. You learned how to write a program that has source code divided among mul-

tiple files or modules. This practice, called modular programming, makes it easy to reuse

general-purpose functions in more than one program. You saw how you can use pre-

processor directives to create function macros, for conditional compilation, and other

tasks. Finally, you saw that the compiler provides some function macros for you.

614 Day 21

Graphical IDEs will usually allow you to enter command line arguments into

a dialog box. For example, the Dev-C++ compiler included on the CD of this

book will allow you to enter command line arguments by selecting the para-

meter button on the compilation dialog. Figure 21.5 shows the dialog after

the parameter button has been pressed.

Note

FIGURE21.5

The parameters button.

DOuseargcandargvas the variable

names for the command-line arguments

formain(). Most C programmers are

familiar with these names.

DON’Tassume that users will enter the

correct number of command-line para-

meters. Check to be sure they did; and if

not, display a message explaining the

arguments they should enter.

DO DON’T

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