Another common task in programming is working with numbers, so it shouldn’t surprise us that PHP comes with some handy built-in functions for working with numbers.
abs() function returns the absolute value of its number argument:
echo abs(-10.99); // Prints: 10.99 echo abs(127); // Prints: 127
Another useful function is the
round() function which returns the nearest integer to its number argument:
echo round(1.2); // Prints: 1 echo round(1.5); // Prints: 2 echo round(1298736.821763876); // Prints: 1298737
You’re going to write a function which uses the
abs() built-in function within its definition.
Write a function called
calculateDistance() that calculates the distance between two numbers. The function should return the same result for two arguments no matter what order they’re passed into the function.
Here are some examples of how the function should work:
calculateDistance(-1, 4)should return 5
calculateDistance(4, -1)should return 5
calculateDistance(3, 7)should return 4
calculateDistance(7, 3)should return 4
Once you’ve finished writing your function, you should run it to make sure it’s working how it should.
Check out the hint if you want some help on the strategy or a reminder about how to define your own functions.
Awesome! This time you’re going to write a function which uses the
Write a function
calculateTip() which takes a number representing the total cost of a meal as its argument.
Your function should calculate a new total with an 18% tip added and return that value rounded to the nearest integer.
Your function must invoke the built-in
calculateTip(100)should return 118
calculateTip(35)should return 41
calculateTip(88.77)should return 105