Just an Average Day

🔖 Background Information

The Java Stream API gives developers the power to use functional programming techniques on problems that were usually solved with classes in Java. This has a variety of benefits including potential performance gains, the ability to parallelize code, and the ability to model your code as a series of data transformations.

🎯 Problem Statement

1. Write a set of four functions that calculate the minimum, maximum, sum, and average of an array of integers. These functions should use a for loop like we have seen in the class many times before.
2. Write a set of four functions that calculate the minimum, maximum, sum, and average of an array of integers. These functions should use the Java Stream API.

✅ Acceptance Criteria

• I expect to see eight functions total.
• Test your functions thoroughly through JUnit tests.

📋 Dev Notes

• You are allowed to use any and all helper functions included in the Stream API.

🖥️ Example Output

You might define your eight functions like so:

public int maximumUsingForLoop(int[] nums) { ... }
public int minimumUsingForLoop(int[] nums) { ... }
public int sumUsingForLoop(int[] nums) { ... }
public int averageUsingForLoop(int[] nums) { ... }
 
public int maximumUsingStream(int[] nums) { ... }
public int minimumUsingStream(int[] nums) { ... }
public int sumUsingStream(int[] nums) { ... }
public int averageUsingStream(int[] nums) { ... }

📝 Thought Provoking Questions

1. Which syntax do you prefer for these calculations - streams or loops? Why?
2. What is the difference between a “mutable” and “immutable” structure in Java?
3. What does the map function do in a stream?
4. What does the filter function do in a stream?
5. What does the reduce function do in a stream?

💼 Optional Extra Credit

(1/4 Point) Evens Only

Write a function that takes an array of integers and filters out any odd numbers. You must use the Java Stream API for this solution and test it using JUnit.

(1/4 Point) Odds Only

Write a function that takes an array of integers and filters out any even numbers. You must use the Java Stream API for this solution and test it using JUnit.

(1/4 Point) Add Five

Write a function that takes an array of integers and returns a new array of integers where all of the numbers have been incremented by five. You must use the Java Stream API for this solution and test it using JUnit.

(1/4 Point) Square Numbers

Write a function that takes an array of integers and returns a new array of integers where all of the numbers have been squared. You must use the Java Stream API for this solution and test it using JUnit.

🔗 Useful Links

• Java Project Template

📘 Works Cited

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