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Reading from the terminal

Reading from the terminal

To read input from the terminal, there are a number of readXXX-methods. The methods are part of the scala.io.StdIn object, so you have to import them before you can use them, for instance like this:

import scala.io.StdIn.{readLine,readInt}

The most important functions are

• readLine() reads a line and returns it as a string (without the new-line character at the end);
• readLine(prompt) prints a prompt and then reads a line as above, as in this example:

  val s = readLine("What do you say? ")
  println("You said: '" + s + "'")
  

• readInt() reads a line and returns it as an integer;
• readDouble() reads a line and returns a floating point number;
• readBoolean() reads a line and returns a Boolean ( "yes", "y", "true", and "t" for true, and anything else for false); and
• readChar() reads a line and returns the first character.

For instance:

import scala.io.StdIn.{readInt,readBoolean}

print("How many beer? ")
val n = readInt()
printf("You ordered %d beer\n", n)
print("Are you sure? ")
if (readBoolean())
  printf("Serving %d beer\n", n)