LESSON 178 OF 414 · PROJECTS: EVERYDAY PROGRAMS

Report Card V5 - Subject to Grade Dictionary in Scala

Practice

Use a dictionary, a loop, and conditionals to print each subject with its letter grade in alphabetical order.

You start with:

val grades = scala.collection.mutable.TreeMap[String, Int]()
grades("Math") = 92
grades("English") = 78
grades("Science") = 85
grades("History") = 67

Build:

English: C
History: D
Math: A
Science: B

Rules:

Visit the subjects in alphabetical order.
Look up each subject's score in the dictionary and apply the grading scale (90+ A, 80s B, 70s C, 60s D, else F).
On each iteration print the subject, a colon and a space, then the grade, for example English: C.

Use a TreeMap - it iterates its keys in sorted order automatically.

val grades = scala.collection.mutable.TreeMap[String, Int]()
grades("Math") = 92
grades("English") = 78
grades("Science") = 85
grades("History") = 67

for (subject <- grades.keys) {
    val score = grades(subject)
    var grade = ""
    if (score >= 90) {
        grade = "A"
    } else if (score >= 80) {
        grade = "B"
    } else if (score >= 70) {
        grade = "C"
    } else if (score >= 60) {
        grade = "D"
    } else {
        grade = "F"
    }
    println(subject + ": " + grade)
}

STEP 1 OF 9

Guided

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Report Card V5 - Subject to Grade Dictionary in Scala

Report Card V5 in Scala