Find trimmed average of an array excluding the min and max value

Question

was looking to find the trimmed average of an array but am stumped on how to implement it using a method. Please shoot any ideas on how to implement and get the actual trimmed average using a method. This is all I have at the moment. TIA!

public static void main(String[] args) {
    // Program 1: Average, Min, Max, Trimmed Average of Array
    Scanner in = new Scanner(System.in);
    int array[] = new int[] {88,48,96,85,97,68,97};

    // Calling getMax() method for getting max value
    int max = getMax(array);
    System.out.println("Maximum: " + max);

    // Calling getMin() method for getting min value
    int min = getMin(array);
    System.out.println("Minimum: " + min);

    // calling getAvg() method for getting avg value
    double avg = getAvg(array);
    System.out.println("Average: " + avg);

    // calling getMean() method for getting trimmed mean value
    double mean = getTrim(array);
    System.out.println("Trimmed mean: " + mean);
}

// Method for getting the maximum value
public static int getMax(int[] inputArray) {
    int maxValue = inputArray[0];
    for (int i = 1; i < inputArray.length; i++) {
        if (inputArray[i] > maxValue) {
            maxValue = inputArray[i];
        }
    }
    return maxValue;
}

// Method for getting the minimum value
public static int getMin(int[] inputArray) {
    int minValue = inputArray[0];
    for (int i = 1; i < inputArray.length; i++) {
        if (inputArray[i] < minValue) {
            minValue = inputArray[i];
        }
    }
    return minValue;
}

//Method for getting the avg value
public static double getAvg(int[] inputArray) {
    double total = 0;
    double avg;
    for(int i=0; i<inputArray.length; i++){
        total = total + inputArray[i];
    }
    return avg = total / inputArray.length;
}

//Method for getting the trimmed mean value
public static double getTrim(int[] inputArray) {

}

}

Answer 1

Here's the fully finished program :D

public static void main(String[] args) {
    // Program 1: Average, Min, Max, Trimmed Average of Array
    Scanner in = new Scanner(System.in);
    int array[] = new int[] { 88, 48, 96, 85, 97, 68, 97 };

    int max = getMax(array);
    System.out.println("Maximum: " + max);

    int min = getMin(array);
    System.out.println("Minimum: " + min);

    double avg = getAvg(array);
    System.out.println("Average: " + avg);

    double mean = getTrim(array);
    System.out.println("Trimmed mean: " + mean);
}

public static int getMax(int[] inputArray) {
    int maxValue = inputArray[0];
    for (int i = 1; i < inputArray.length; i++) {
        if (inputArray[i] > maxValue) {
            maxValue = inputArray[i];
        }
    }
    return maxValue;
}

public static int getMin(int[] inputArray) {
    int minValue = inputArray[0];
    for (int i = 1; i < inputArray.length; i++) {
        if (inputArray[i] < minValue) {
            minValue = inputArray[i];
        }
    }
    return minValue;
}

public static double getAvg(int[] inputArray) {
    double total = 0;
    double avg;
    for (int i = 0; i < inputArray.length; i++) {
        total = total + inputArray[i];
    }
    return avg = total / inputArray.length;
}

public static double getTrim(int[] inputArray) {
    int max = getMax(inputArray);
    int min = getMin(inputArray);
    double sum = 0;
    for (int i = 0; i < inputArray.length; i++) {
        sum = sum + inputArray[i];
        if (inputArray[i] > max) {
            max = inputArray[i];
        }
        if (inputArray[i] < min) {
            min = inputArray[i];
        }
    }
    return ((double) (sum - max - min)) / (inputArray.length - 2);
}

}

Answer 2

Try this:

public static double avgExcludingMinMax(int[] inputArray) {
    int max = inputArray[0];
    int min = inputArray[0];
    long sum = 0;
    for(int i = 0; i < inputArray.length; i++){
        sum = sum + inputArray[i];
        if (inputArray[i] > max) {
            max = inputArray[i];
        }
        if (inputArray[i] < min) {
            min = inputArray[i];
        }
    }
    return ((double) (sum - max - min)) / (inputArray.length - 2);
}

Note that this will throw an exception if inputArray.length == 0;

If you want to read more about the statistical background of such an operation, check out https://en.wikipedia.org/wiki/Trimmed_estimator and https://en.wikipedia.org/wiki/Winsorizing!