Teach Yourself Borland C++ in 14 Days - portal

NOTE
Wading In Deeper
If the conditional expression evaluates to false, the code block associated with the if
expression is ignored, and program execution continues with the first statement following the
code block.
C++ contains a lot of shortcuts. One of those shortcuts involves using
just the variable name to test for true. Look at this code:
if (fileGood) ReadData();
This method is a shortcut for the longer form, which is illustrated with
this line:
if (fileGood == true) ReadData();
This example uses a bool variable, but any data type will do. The
expression evaluates to true as long as the variable contains any nonzero
value. You can test for false by applying the logical NOT (!)
operator to a variable name:
bool fileGood = OpenSomeFile();
if (!fileGood) ReportError();
Learning the C++ shortcuts will help you write code that contains a
degree of elegance. Knowing the shortcuts also helps you understand
C++ code that you read in examples and sample listings.
In some cases you want to perform an action if the conditional expression evaluates to true
and perform some other action if the conditional expression evaluates to false. In this case
you can implement the else statement:
if (x == 20) {
DoSomething(x);
}
else {
DoADifferentThing(x);
}
NEW TERM
The else statement is used in conjunction with the if statement and identifies
sections of code that are executed when the if statement fails (that is, evaluates to
false).
In this example one of the two functions will be called, but not both.
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