Decisions

The windshield wiper decision is a two-way decision (sometimes called a binary decision). The decision seems small, but in programming, complicated decisions are made of many small decisions. Here is a program that implements the wiper decision:

import java.util.Scanner;
class RainTester
{
  public static void main (String[] args) 
  {
    Scanner scan = new Scanner( System.in );
    String answer;

    System.out.print("Is it raining? (Y or N): ");
    answer =  scan.nextLine();
    
    if ( answer.equals("Y") )                // is answer exactly "Y" ?              
      System.out.println("Wipers On");              // true branch
    else
      System.out.println("Wipers Off");             // false branch   
  }
}

The user is prompted to answer with a single character, Y or N :

System.out.print("Is it raining? (Y or N): ");

The Scanner reads in whatever the user enters (even if the user enters more than one character):

answer =  scan.nextLine();

The if statement tests if the user entered exactly the character Y (and nothing else):

if ( answer.equals("Y") )  // is answer exactly "Y" ?              

If so, then the statement labeled "true branch" is executed. Otherwise, the statement labeled "false branch" is executed.

The "true branch" is separated from the "false branch" by the reserved word else.