RollLoadedDie.java

Below is the syntax highlighted version of RollLoadedDie.java from §1.3 Conditionals and Loops.

/******************************************************************************
 *  Compilation:  javac RollLoadedDie.java
 *  Execution:    java RollLoadedDie
 *
 *  Simulate the roll of a loaded six-sided die, where the values
 *  1, 2, 3, 4, and 5 appear with probability 1/8 and the value 6
 *  appears with probablity 3/8, and print the resulting number.
 *
 *  % java RollLoadedDie
 *  4
 *
 *  % java RollLoadedDie
 *  6
 *
 ******************************************************************************/

public class RollLoadedDie {
    public static void main(String[] args) {

        // double in the range [0.0, 1.0)
        double r = Math.random();

        // integer in the range 1 to 6 with desired probabilities
        int roll;
        if      (r < 1.0/8.0) roll = 1;
        else if (r < 2.0/8.0) roll = 2;
        else if (r < 3.0/8.0) roll = 3;
        else if (r < 4.0/8.0) roll = 4;
        else if (r < 5.0/8.0) roll = 5;
        else                  roll = 6;

        // print result
        System.out.println(roll);
    }
}