Now, let's explore a scenario where multiple conditions come into play:

The drawbacks of this code are that each condition is checked separately, even after one has already been found true, leading to unnecessary checks and inefficiency. Additionally, because separate if statements are used, it's not possible to add an else condition to handle cases when none of the conditions are true. Moreover, if the value of the $day variable theoretically matches multiple conditions, the code would output multiple messages at once. To optimize this, you could use an if ... else if ... else construct, which would avoid redundant checks and allow for a default case.

Introducing else if

The else if construct provides a solution for selecting a specific code block within a series of conditions:

This pseudocode demonstrates sequential conditional checks using if, else if, and else. The program selects the first block of code whose condition evaluates to true, otherwise moves to the next else if. Let's apply this to our example:

Now, we've created a sequence of conditions. When at least one if condition becomes true, the chain is interrupted.

Note

This structure is useful when you only need one condition to be satisfied.

Adding else

You can also add an else statement after the condition chain. Let's modify our example: