PHP: Conditional constructions (if)
The task of a predicate is to get an answer to a question, but usually this isn't enough; you often have to perform a certain action depending on the answer.
Let's write a function that determines the type of a sentence that's passed to it. To begin with, it will distinguish between normal sentences and question sentences.
<?php
function getTypeOfSentence($sentence)
{
// a simple way to extract the last character
$lastChar = $sentence[-1];
if ($lastChar === '?') {
return 'question';
}
return 'normal';
}
getTypeOfSentence('Hodor'); // normal
getTypeOfSentence('Hodor?'); // question
if is an instruction. You need to pass predicate expression to it in parentheses and then define a block of code in curly brackets. This code block executes only if the predicate is true.
If the predicate is false, we skip the code block in curly brackets, and the function keeps executing. In our case, the next line of code, return 'normal'; will make the function return the string and terminate.
As you can see, return can be anywhere in a function. Including within a conditional code block.
If the curly brackets after if contain only one line of code, you can leave out the brackets:
<?php
function getTypeOfSentence($sentence)
{
$lastChar = $sentence[-1];
if ($lastChar === '?')
return 'question';
return 'normal';
}
print_r(getTypeOfSentence('Hodor')); // => normal
print_r("\n");
print_r(getTypeOfSentence('Hodor?')); // => question
We recommend not doing that and always writing curly brackets. That way, you can clearly see where the conditional construction body starts and ends. The code becomes clearer and more readable.
Instructions
Implement a function, guessNumber(), which takes a number and checks if the number is equal to a given number (let it be 42). If it's equal, the function should return the string 'You win!', otherwise, it should return the string 'Try again!'.
<?php
guessNumber(42) // 'You win!'
guessNumber(61) // 'Try again!'
The exercise doesn't pass checking. What to do? 😶
If you've reached a deadlock it's time to ask your question in the «Discussions». How ask a question correctly:
- Be sure to attach the test output, without it it's almost impossible to figure out what went wrong, even if you show your code. It's complicated for developers to execute code in their heads, but having a mistake before their eyes most probably will be helpful.
In my environment the code works, but not here 🤨
Tests are designed so that they test the solution in different ways and against different data. Often the solution works with one kind of input data but doesn't work with others. Check the «Tests» tab to figure this out, you can find hints at the error output.
My code is different from the teacher's one 🤔
It's fine. 🙆 One task in programming can be solved in many different ways. If your code passed all tests, it complies with the task conditions.
In some rare cases, the solution may be adjusted to the tests, but this can be seen immediately.
I've read the lessons but nothing is clear 🙄
It's hard to make educational materials that will suit everyone. We do our best but there is always something to improve. If you see a material that is not clear to you, describe the problem in “Discussions”. It will be great if you'll write unclear points in the question form. Usually, we need a few days for corrections.
By the way, you can participate in courses improvement. There is a link below to the lessons course code which you can edit right in your browser.
Definitions
A conditional construct is a way to set a condition for code execution. For example
if ($x > 10) { ... }