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Unit 3: Flow-Control Statements and PHP in Web Page

if (is_int($x)) { Notes
echo ($x . ‘ is an integer’);
}

elseif (is_float($x)) {
echo ($x . ‘ is a floating point number’);

}
elseif (is_string($x)) {
echo ($x . ‘ is a string’);
}

elseif (is_bool($x)) {
echo ($x . ‘ is a boolean’);
}

else {
echo ($x . ‘ is not a primitive data type’);
}

3.1.2 Switch Statement
Although you can test for multiple conditions with a series of if statements, the if statement really
does only test the truth of a single conditional expression at a time. It is a two-state expression,
either the statement block executes or it does not.

If you want to check a single variable for multiple values, you can do so with a series of if
statements, but this is not always the best approach. PHP also provides a conditional statement
for testing multiple values for a single variable or expression. This is the switch statement.
The switch statement, in its structure, is similar to the if statement. It takes an expression to be
evaluated and a statement block.
The switch statement can only evaluate a single expression, but it can compare that single
expression to a series of possible values. The expression to be evaluated is most likely not a
conditional, since a conditional only has two possible states something best handled by
an if ... else statement. Rather it is usually some expression that can have a series of values, such
as a variable that can have a number between 0 and 9, or a form field that can contain one of the
fifty-two-character abbreviations for the US state names.
switch (expression) {
statements;

}
Although the shell of the statement is the same, the body of the statement block is significantly
more complex and requires additional keywords to make the statement work. A full switch
statement may look like the following example:

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