Exercise 1
Create a file named A4.java. Place all your code in this file.
The factorial (!) is defined as follows:
n! = n * (n - 1) * (n - 2) * ... * 3 * 2 * 1
For example, 5! = 5 * 4 * 3 * 2 * 1 = 120
Write a function named factorial that takes as input an int and returns an int. Your function should
verify that the input is non-negative If the input is not valid, return -1.
If it is valid, your function should compute the value of the factorial using a for loop and return
the value.
Hint: The factorial of 0 is 1.
Hint: A for loop will not execute if the condition is immediately false.
Exercise 2
Create a method with the following header:
public static int countTriple(String str)
Define it as follows:
1
We'll say that a "triple" in a string is a char appearing three times in a row. Return the number of
triples in the given string. The triples may overlap.
countTriple("abcXXXabc") ? 1
countTriple("xxxabyyyycd") ? 3
countTriple("a") ? 0
Exercise 3
Create a method with the following header:
public static boolean haveThree(int[] nums)
Define it as follows:
Given an array of ints, return true if the value 3 appears in the array exactly 3 times, and no 3's are
next to each other.
haveThree([3, 1, 3, 1, 3]) ? true
haveThree([3, 1, 3, 3]) ? false
haveThree([3, 4, 3, 3, 4]) ? false
