Objective
Create a program that asks the user to input two integers and then outputs their sum.
Description
In this exercise, you have to create a program that asks the user to input two integers, one-by-one, and then outputs their sum.
The first input prompt of the program should be of the form shown below:
Here, <input> denotes the input of the user.
Similarly, the second input should be of the form:
The output should be:
where <sum> is the sum of the input integers.
Shown below is an example:
New file
Inside the directory you created for this course on PHP, create a new folder called Exercise-1-Addition-Calculator and put the .php solution files for this exercise within it.
Solution
As instructed in the question, first we need to ask the user to input a value for x and then a value for y, with the prompts 'x: ' and 'y: ', respectively.
<?php
echo 'x: ';
$y = fgets(STDIN);
echo 'y: ';
$x = fgets(STDIN);$a and $b, but since the prompt messages specifically use the names 'x' and 'y', it would be straightforward to go with these names for the variables as well.Next, up we need to convert both $x and $y to integers using the (int) typecast:
<?php
echo 'x: ';
$y = fgets(STDIN);
echo 'y: ';
$x = fgets(STDIN);
// Convert to int.
$x = (int) $x;
$y = (int) $y;Finally, we just ought to add x and y together and print out the result, as desired in the exercise.
<?php
echo 'x: ';
$x = fgets(STDIN);
echo 'y: ';
$y = fgets(STDIN);
// Convert to int.
$x = (int) $x;
$y = (int) $y;
echo 'The sum is: ', $x + $y;Below, we use this program to add two numbers:
Slight improvement
Note that instead of converting the variables separately in lines 10 - 11 above, we could have used the (int) typecast directly before the fgets() call (in lines 4 and 7). This is definitely much more compact than the code above.
<?php
echo 'x: ';
$x = (int) fgets(STDIN);
echo 'y: ';
$y = (int) fgets(STDIN);
echo 'The sum is: ', $x + $y;Semantically, this code snippet is exactly similar to the last one i.e. both the code snippets do exactly the same thing.
