script.js

/*
GRADEBOOK APP

Step 1 = Identifying the building blocks

getAverage
getGrade
hasPassingGrade
studentMsg

Think of each function as a lone worker
then they'll need to ebe combined together to make the app work
*/

function getAverage(scores) {
    let total = 0; // need a variable that can store the total value
    if(scores.length == 0){
        return 0;
    }
    for(let i = 0; i < scores.length; i++) { // the for loop is the choice
        total += scores[i];
        // need to accumulate to find the sum of all values
        // and the scores[i] (calculated each iteration)
    }
    let average = total / scores.length; 
    // total = sum of all values
    // scores.length = number of the values
    return average; // return of the average score
};


// getGrade - the order of the grades matters
// from the A case to the F case
function getGrade(score) {
   // decision making - the if/else statement
   if(score == 100) {
    return "A+";
   } else if(score >= 90 && score <= 99) {
    return "A";
   } else if(score >= 80 && score <= 89) {
    return "B";
   } else if(score >= 70 && score <= 79) {
    return "C";
   } else if(score >= 60 && score <= 69) {
    return "D";
   } else { // because everything else has being calculated
    // there's no need of a condition here
    return "F";
   }

}; 



function hasPassingGrade(score) {
    // a passing grade is anything different from F
    // so instead of asking if they passed, I'll ask if they failed
    if(getGrade(score) != "F"){
        return true;
    } else {
        return false;
    }
}; // it uses getGrade to find its value


// because the system already gives me the grade
// I can rely on the outputs only (and not comparing them)
function studentMsg(scores, studentScore) {
    // scores = all the class scores
    // studentScore = the individual student score
    let average = getAverage(scores);
    // the average variable is defined in getAverage but it exists only in that function
    // so in this way I'm defyining it here too
    let grade = getGrade(studentScore); // similar to the previous
    // I'm reusing the function rather than re-calculating/comparing values

    if(!hasPassingGrade(studentScore)){
        return `Class average: ${average}.
        Your grade: ${grade}. You failed the course.`
    } else {
        return `Class average: ${average}.
        Your grade: ${grade}. You passed the course.`
    }; // I've tried string concatenation but this way the code looks cleaner
} 
console.log(studentMsg([92, 88, 12, 77, 57, 100, 67, 38, 97, 89], 37));