On the AP Computer Science Exam, you will be expected to be familiar with Math.random. You may be asked to use it to generate a random value within a specific range, generate a random valid index in an array or list, or make a conditional statement true with a specific probability.
The AP CS Elevens Lab and the AP CS Magpie Lab feature random number generation.
ArrayList<String> names = new ArrayList<String>(); names.add("Brandon"); names.add("Brenda"); /* code to add many more names to names */ String randomName = /* select a random name from names */;
Give code to replace /* select a random name from names */. Each name in names must have an equal probability of being selected.
double a = /* a number > 0 */
double b = /* a number > a */
Modify the statement below such that a <= r < b and that each value in the range has an equal probability of being assigned to r.
double r = Math.random();
if(/* condition */)
/* statement */
Give code to replace /* condition */ such that /* statement */ will have a 25% probability of being executed when the code is run.