Conditional and Random Behavior

Review

 

Example: The code

        Random generator = new Random();
        int randNum = generator.nextInt(10);

creates a random number generator and uses it to generate one of the 10 numbers between 0 and 9 (the parameter specifies the number of possible values). If we call nextInt(10) repeatedly, we'll get a sequence of pseudo-random numbers in that range, such as:

        8, 5, 0, 0, 4, 3, 1, 3, 1, 0, 3, 6, 7, 0, 4, 4, 3, 9, 2, 8, ...

The Random class is in the java.util package.

Think — Pair — Share

Consider the following program:

Example: Choosing Randomly

Random generator = new Random();
int randNum = generator.nextInt(100);
if ( randNum < 4 )
    student.setFirstDestination("Volunteer / Service Opportunity");
else if ( randNum < 23 )
    student.setFirstDestination("Continuing Education");
else
{
    randNum = generator.nextInt(100);
    if ( randNum < 91 )
        student.setFirstDestination("Employed");
    else
        student.setFirstDestination("Unknown");
} 
  

• What is the probability that the given student object has "Volunteer / Service Opportunity" as the first destination?
• What is the probability that the given student object has "Continuing Education" as the first destination?
• What is the probability that the given student object has "Employed" as the first destination?
• What is the probability that the given student object has "Unknown" as the first destination?
• Why doesn't the line that gets the 2nd random number have int at the beginning?