This section provides a tutorial example on how to use different types of 'if' statements to control code executions.
To help us understand how "if" statements work, I wrote the following the tutorial example PHP script:
<?php # IfStatements.php
# Copyright (c) 2003 by Dr. Herong Yang. http://www.herongyang.com/
#
print("\n Single-statement \"if\":\n");
$isNewYear = TRUE;
if (isNewYear) print(" Happy New Year!\n");
print("\n Multi-statement \"if\":\n");
$hasError = TRUE;
if ($hasError) {
print(" Open the log file.\n");
print(" Write an error message.\n");
print(" Close the log file.\n");
}
print("\n \"if ... else\" statement:\n");
$login = "Herong";
if ($login == "Admin") {
print(" Display the delete button.\n");
print(" Display the edit button.\n");
} else {
print(" Display the view button.\n");
}
print("\n \"if ... elseif\" statement:\n");
$dateInfo = getdate();
$wDay = $dateInfo["wday"];
$weekDay = $dateInfo["weekday"];
$openHours = "open";
if ($wDay == 0) {
$openHours = "closed";
} elseif ($wDay >= 1 && $wDay <= 5) {
$openHours = "open from 9:00am to 9:00pm";
} elseif ($wDay == 6 ) {
$openHours = "open from 9:00am to 5:00pm";
} else {
$openHours = "not at here";
}
print(" Today is: $weekDay\n");
print(" The library is $openHours\n");
?>
If you run this sample script, you should get:
Single-statement "if":
Happy New Year!
Multi-statement "if":
Open the log file.
Write an error message.
Close the log file.
"if ... else" statement:
Display the view button.
"if ... elseif" statement:
Today is: Sunday
The library is closed
