microsoft/qdk

// # Sample
// Conditional Branching
//
// # Description
// Q# supports three branching keywords: `if`, `elif`, and `else`. These behave in the normal
// way, if you're familiar with if expressions or statements in other languages. One key distinction
// in Q# is that ifs are expressions, not statements. That means that they can return values, and
// they effectively perform the job of both ternary expressions and if statements in other languages.
// If expressions allow your code to branch, or conditionally execute parts of a Q# program.

function Main() : Unit {
    let number = 5;
    // Conditionally messages "Fizz" if the `number`, in this case 5, is divisible by 3.
    // Since 5 is not divisible by 3, the message "Fizz" will not be printed.
    if number % 3 == 0 { Message("Fizz"); }

    // Conditionally messages "Buzz" if the `number`, in this case 5, is divisible by 5.
    // Since 5 is divisible by 5, the message "Buzz" will be printed.
    if number % 5 == 0 { Message("Buzz"); }

    let fahrenheit = 40;

    // In this example, we print a message based on the temperature. The
    // message that will be printed is "It is livable".
    // `elif` allows you to express successive conditional expressions, with each
    // successive condition only being evaluated if the previous one was false.
    if fahrenheit <= 32 {
        Message("It's freezing");
    } elif fahrenheit <= 85 {
        Message("It is livable");
    } else {
        Message("It is way too hot");
    }
    let fahrenheit = -40;
    // `if` can also be used as an expression, to conditionally return a value.
    let absoluteValue = if fahrenheit > 0 { fahrenheit } else { fahrenheit * -1 };
    Message($"Absolute value of {fahrenheit} is {absoluteValue}");
}