Code Snippet: Prompt for Yes or No

Within these castle walls be forged Mavens of Computer Science ...

— Merlin, The Coder

Prompt the user to input either a "yes" or a "no"

Swift

// Prompt the user for 'yes' or 'no'
var line : String?
repeat {
     print("Please enter 'yes' or 'no' ->", terminator:"")
     line = readLine()
} while (line == nil || (line! != "yes" && line! != "no")) 

// By the time we get here, line! is either "yes" or "no"

Python

text = input("Please enter 'yes' or 'no' ->")
while text != "yes" and text != "no":
    text = input("Please enter 'yes' or 'no' ->")

Java

Scanner input = new Scanner(System.in); // don't forget to import Scanner in java.util
System.out.print("Please enter 'yes' or 'no': "); // use println to go to the next line
String userInput = input.next(); // for string in same line
// Look up Scanner java for more information