CODEWITHSUNDEEP
javaarrays
Lily Tottrup
Lily Tottrup

Reputation: 21

percentages in an array of varying input

I'm working on an assignment for my computer course and our task is to write a method that analyzes the array "numbers" and return an array representing for each digit, the proportion of times it occurred as a leading digit...

ie { 100, 200.1, 9.3, 10} then 1 occurs as a leading digit 50 % of the time, 2 occurs 25% of the time, and 9 occurs 25 % of the time, so your produced array should contain: {0, .5, .25, 0, 0, 0, 0, 0, 0, .25}

I'm having issues getting started, it's suggested that we write a helper method called, for example, countLeadingDigits which returns an array of counts for each digit and only then calculate the percentages. I don't know how to go about writing the method that takes an unknown number of input doubles from the user then store the number of times each digit appears as a leading digit.. I've already written the part of the code that calculates the leading digit. Any hints pleasee?

Upvotes: 2

Views: 351

Answers (1)

Juvanis
Juvanis

Reputation: 25950

A solution with short and intense code:

public static void main(String[] args)
{
    double[] inputs = { 100, 200.1, 9.3, 10 , -100 }; // your inputs
    double sum = inputs.length;

    int[] leadingDigitCounters = new int[10]; // counters for 0...9

    // Here is how you increment respective leading-digit counters
    for (double d : inputs) 
    {
        int j = Integer.parseInt((d + "").replace("-", "").charAt(0) + "");
        leadingDigitCounters[j]++;
    }   

    // Printing out respective percentages
    for (int i : leadingDigitCounters)
        System.out.print((i / sum) + " ");
}

Output:

0.0 0.6 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.2

Upvotes: 1

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