AP Computer Science --- Haas --- BirthdayArray

Objective: Using Arrays

Birthday problem. What are the chances that two or more people in a room share the same birthday?

Part I:
Suppose that people enter an empty room until a pair of people share a birthday. On average, how many people will have to enter before there is a match? Write a program Birthday.java to calculate this probability by simulation. Assume birthdays are uniform random integers from 1 to 365. Your program will place random numbers (birthdays) into an array until a number (birthday) repeats. Have this process repeat 100 times, print out the results each time. Find the average of these 100 trials.

Part II:
This is a slight variation of the first progam. Now assume you have a classroom with 28 students. What are the odds that at least two have the same birthday? Again write a program to calculate this probability by simulation. Fill an array with 28 random numbers from 1 to 365. Determine if two or more birthdays are the same. Repeat 100 times, print out the results each time, and print the total number of times birthdays are the same.