microsoft/qdk
Publicmirrored fromhttps://github.com/microsoft/qdkAvailable
samples/language/ConditionalBranching.qs
38lines · modecode
| 1 | // # Sample |
| 2 | // Conditional Branching |
| 3 | // |
| 4 | // # Description |
| 5 | // Q# supports three branching keywords: `if`, `elif`, and `else`. These behave in the normal |
| 6 | // way, if you're familiar with if expressions or statements in other languages. One key distinction |
| 7 | // in Q# is that ifs are expressions, not statements. That means that they can return values, and |
| 8 | // they effectively perform the job of both ternary expressions and if statements in other languages. |
| 9 | // If expressions allow your code to branch, or conditionally execute parts of a Q# program. |
| 10 | |
| 11 | function Main() : Unit { |
| 12 | let number = 5; |
| 13 | // Conditionally messages "Fizz" if the `number`, in this case 5, is divisible by 3. |
| 14 | // Since 5 is not divisible by 3, the message "Fizz" will not be printed. |
| 15 | if number % 3 == 0 { Message("Fizz"); } |
| 16 | |
| 17 | // Conditionally messages "Buzz" if the `number`, in this case 5, is divisible by 5. |
| 18 | // Since 5 is divisible by 5, the message "Buzz" will be printed. |
| 19 | if number % 5 == 0 { Message("Buzz"); } |
| 20 | |
| 21 | let fahrenheit = 40; |
| 22 | |
| 23 | // In this example, we print a message based on the temperature. The |
| 24 | // message that will be printed is "It is livable". |
| 25 | // `elif` allows you to express successive conditional expressions, with each |
| 26 | // successive condition only being evaluated if the previous one was false. |
| 27 | if fahrenheit <= 32 { |
| 28 | Message("It's freezing"); |
| 29 | } elif fahrenheit <= 85 { |
| 30 | Message("It is livable"); |
| 31 | } else { |
| 32 | Message("It is way too hot"); |
| 33 | } |
| 34 | let fahrenheit = -40; |
| 35 | // `if` can also be used as an expression, to conditionally return a value. |
| 36 | let absoluteValue = if fahrenheit > 0 { fahrenheit } else { fahrenheit * -1 }; |
| 37 | Message($"Absolute value of {fahrenheit} is {absoluteValue}"); |
| 38 | } |
| 39 | |