Problem 01

Problem Statement

You're working with a sequence of numbers and need to find out how many of them are even. To do this, create a function named countEvens that counts the number of even integers in a given array.

The countEvens function should accept one parameter:

1. numbers: an array of integers.

An integer is considered even if it is divisible by 2 with no remainder. The function should return the count of such even numbers in the array.

Here are some examples:

• countEvens([2, 1, 2, 3, 4]) should return 3 because there are three even numbers (2, 2, 4).

{Try It!}(node .guides/countEvens/try-it-01.js)

• countEvens([2, 2, 0]) should return 3 because all the numbers (2, 2, 0) are even.

{Try It!}(node .guides/countEvens/try-it-02.js)

• countEvens([1, 3, 5]) should return 0 because there are no even numbers.

{Try It!}(node .guides/countEvens/try-it-03.js)

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Solution

{Check It!|assessment} node .guides/secure/countEvensTest.js

Test Cases

1. Test Case 1:

   • Input: countEvens([2, 1, 2, 3, 4])
   • Expected Output: 3
   • Explanation: The array contains three even numbers: 2, 2, and 4.

2. Test Case 2:

   • Input: countEvens([2, 2, 0])
   • Expected Output: 3
   • Explanation: All the numbers in the array are even: 2, 2, and 0.

3. Test Case 3:

   • Input: countEvens([1, 3, 5])
   • Expected Output: 0
   • Explanation: There are no even numbers in the array.

4. Test Case 4:

   • Input: countEvens([0, 1, -2, -3, 4])
   • Expected Output: 3
   • Explanation: There are three even numbers in the array: 0, -2, and 4.

5. Test Case 5:

   • Input: countEvens([11, 23, 35, 47])
   • Expected Output: 0
   • Explanation: There are no even numbers in the array.

Problem 02

Problem Statement

You are given an array of integers, which has at least one element. Your task is to create a function named bigDiff that finds the difference between the largest and smallest values in the array.

The bigDiff function should accept one parameter:

1. numbers: an array of integers.

The function should calculate the difference between the maximum and minimum values in the array. You can use the built-in Math.min() and Math.max() methods to find the smallest and largest values, respectively.

Here are some examples:

• bigDiff([10, 3, 5, 6]) should return 7, as the difference between the largest (10) and smallest (3) values is 7.

{Try It!}(node .guides/bigDiff/try-it-01.js)

• bigDiff([7, 2, 10, 9]) should return 8, since the largest value is 10 and the smallest is 2.

{Try It!}(node .guides/bigDiff/try-it-02.js)

• bigDiff([2, 10, 7, 2]) should return 8, with 10 being the largest and 2 the smallest value.

{Try It!}(node .guides/bigDiff/try-it-03.js)

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Solution

{Check It!|assessment} node .guides/secure/bigDiffTest.js

Test Cases

1. Test Case 1:

   • Input: bigDiff([10, 3, 5, 6])
   • Expected Output: 7
   • Explanation: The difference between the largest (10) and smallest (3) values is 7.

2. Test Case 2:

   • Input: bigDiff([7, 2, 10, 9])
   • Expected Output: 8
   • Explanation: The largest value is 10 and the smallest is 2, so the difference is 8.

3. Test Case 3:

   • Input: bigDiff([2, 10, 7, 2])
   • Expected Output: 8
   • Explanation: Here, the largest value is 10 and the smallest is 2, resulting in a difference of 8.

4. Test Case 4:

   • Input: bigDiff([1, 1, 1, 1])
   • Expected Output: 0
   • Explanation: Since all values are the same (1), the difference is 0.

5. Test Case 5:

   • Input: bigDiff([-3, -1, -4, -2])
   • Expected Output: 3
   • Explanation: The largest value is -1 and the smallest is -4, so the difference is 3.