style="font-size:15px;"> Hello, John!
Hello, James!
Hello, George!
Hello, Maria!
Hello, Peter!
Hello, James!
If and else statement
The if… else statement is used to execute different pieces of code under different conditions.
It has the following construction:
If (conditions) {
Do this.
} elseif (different condition) {
Do that.
} else {
Do something else.
}
Let us create a function that will print a message depending on temperature.
function weather ($F) {
if ($F> 78)
$message=“It is too hot!”;
elseif ($F <65)
$message=“It is too cold!”
else
$message=“Today is nice outside!”;
Return $message.”<br />”;
}
Let us call the function
echo weather (80);
Output: will be “It is too hot!”;
echo weather (60);
Output: will be “It is too cold!”;
echo weather (70);
Output: will be =“Today is nice outside!”;
Switch statement
The switch statement has the following syntax:
switch (variable) {
case label1:
code to be executed if variable =label1;
break;
case label2:
code to be executed if variable =label2;
break;
default:
code to be executed if variable is not equal any label;
}
A Switch Example:
$temperature_C=100;
Switch ($temperature_C) {
Case: 0
$message=“Water freezing point.”;
Break;
Case: 100
$message=“Water boiling point!”:
Break;
Default:
$message=“Neither freezing nor boiling point.”;
}
If we pass in our switch statement variable with the value of 100 we will get Output: “Water boiling point!”
If we pass 0 we will get Output: =“Water freezing point.”
Otherwise, we will get Output: “Neither freezing nor boiling point.”
List
List is a language construction. It is used to assign a list of variables in one operation.
In the line below, I assign array $names from the array example above to a list of variables.
list ($name1, $name2, $name3, $name4, $name5, $name6) = $names;
print ($name5); will print John because it is the 5th name in the array.
Multidimensional Arrays
An example of a two-dimensional array is plane seats. A plane has rows identified by numbers and a few seats in a row identified by letters A, B, C, D, E, and F.
Let us imagine that we have 7 rows with 6 seats in each of the rows. Define an array of seats in a row as $s. Then in two for loops we can create an array of all seats.
$s=array (“A”, “B”, “C”, “D”, “E”, “F”);
for ($i=0; $i <7; $i++) {
$row = $i+1;
for ($j=0; $j <6; $j++) {
$seats [$i] [$j] =$row.$s [$j];
print ($seats [$i] [$j]);
if (($j % 5 ==0) && ($j> 0))
print (”<br>”);
}
}
In an inner J loop, we assign a seat value to the two-dimensional array.
$row = $i +1 because $i starts with 0 and the row starts with 1.
Then we concatenate a row number with a seat letter in $s array.
We insert a line break <br> after every 6 seats.
For that we check if modulo of 5 equals 0. This occurs when $j=5. Since $j starts with 0 we have 6 seats in a row before we insert a break.
Additionally, we check if $j is greater than 0 because 0 modulo 5 gives 0 and creates an extra break we do not want to have.
Output:
1A1B1C1D1E1F
2A2B2C2D2E2F
3A3B3C3D3E3F
4A4B4C4D4E4F
5A5B5C5D5E5F
6A6B6C6D6E6F
7A7B7C7D7E7F
