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    Kotlin
    Java

    • Strings : 14

    • Functions and Algorithms : 13

    • Practice with Functions : 12

    • More About Functions : 11

    • Errors and Debugging : 10

    • Functions : 9

    • Practice with Loops and Algorithms : 8

    • Algorithms I : 7

    • Loops : 6

    • Arrays : 5

    • Compound Conditionals : 4

    • Conditional Expressions and Statements : 3

    • Operations on Variables : 2

    • Variables and Types : 1

    • Hello, world! : 0

    Functions and Algorithms

    Functions are so important that we’re going to continue getting more practice with them. We’ll also discuss the connection between functions and algorithms, the conceptual heart of computer science.

    Throughout this lesson we’ll return to bits of code that we previous implemented as snippets and reimplement them as methods. We’ll also use this as a chance to reinforce some important programming patterns that we’ve already been using.

    Debugging Challenge
    Debugging Challenge

    But let’s start with some debugging practice!

    Array Search
    Array Search

    Next, let’s revisit the code we wrote for array search, rewrite it is a method, and then test it using some sample inputs.

    // Array Search

    Array Is All Larger
    Array Is All Larger

    Our next practice problem has a tricky loop setup. Let’s review that together, and then you can attempt the problem itself.

    // Array Is All Larger Setup
    Created By: Geoffrey Challen
    / Version: 2022.2.0

    Write a method arrayIsAllLarger that, given two Int arrays, returns true if all the values in the first array are larger than or equal to all the values in the same position in the second array. If the first array is longer than the second array, or the second array is longer than the first array, then the extra values can be ignored. If either array is empty, return false.

    For example, given {1, 2, 4} and {0, 1, 7}, you should return false, since 7 is greater than 4. Given {1, 2, 4} and {0, 1} you should return true, since the first two values of the first array are greater than the first two values of the second array. Given {1, 2, 4} and {0, 1, 3, 8}, you should return true, since the first three values of the first array are greater than the first three values of the second array. Given {1, 2} and {1, 2}, you should return true, since all values in the two arrays are equal.

    Array Sum
    Array Sum

    Now, let’s revisit the code we wrote for array sum, rewrite it is a method, and then test it using some sample inputs.

    // Array Sum

    Catchup Quiz Grading
    Catchup Quiz Grading

    As a bit of homework support, let’s talk through how to approach this lesson’s homework problem, since it has another interesting loop setup. We’ll also demonstrate how we can modify the values of arrays that are passed to methods.

    // Catchup Quiz Grading Setup
    Created By: Geoffrey Challen
    / Version: 2022.2.0

    Create a method named catchupGrading that accepts an array of Double values and implements the following catch-up grading policy. Given a score on Quiz N, if a student does better on the next quiz (Quiz N + 1), then you should replace their score on Quiz N with the average of their score on Quiz N and their score on Quiz N + 1. Otherwise, their score on Quiz N is unchanged. Return the number of times that the student does strictly better on the next quiz than they did on the previous one.

    Scores are stored in the array in order. So, given an array with the scores {100.0, 80.0, 90.0}, you would modify the array to contain {100.0, 85.0, 90.0}, and return 1.

    A few hints about how to approach this problem. You'll want to use a loop to go through each pair of scores in the array, so in the loop you'll be examining both one quiz and the next. This loop is similar to but a bit different from the one that we're used to writing. Your function should modify the values in the passed array.

    More Practice

    Need more practice? Head over to the practice page.