Drop highest and lowest of an array in Java

Question

right now I have a project dealing with fractions. The fractions need to be sorted and the highest and lowest are dropped, and then the middle fractions are added together. I have created the array, and done the sort. I am stuck as to how to drop the highest and lowest. Any help is appreciated, thanks!

public class Tester {

public static void main(String[] args) {
    double[] fractions = {(6/7),(2/4),(3/4),(3/18),(1/8),(10/20),(2/6)};
}
public static void selectionSort (int... arr)
{
    int i = 0, j = 0, smallest = 0;
    int temp = 0;

    for (i = 0;i<arr.length - 1;i++)
    {
        smallest = i;
        for (j = 1; j<arr.length - 1; j++)
        {
            if (arr[j]<arr[smallest])
                smallest = j;
        }
        temp = arr[smallest];
        arr[smallest] = arr[i];
        arr[i] = temp;

    }

    //Drop highest and lowest here
}
}

Answer 1

First off you have to add decimal points to either the denominator or numerator in your array initialization to get an array that is not full of 0 's (That way you are not doing integer math). Or simply add a d at the end of your integer math ( 6/7d ).

Next you can sort using Arrays.sort (or continue using your custom sort method) and you can get a sub array using Arrays.copyOfRange . This is very handy since you can give it a starting index and an ending index. Something like this should do the trick:

public static void main(String[] args) {
    double[] fractions = {(6./7),(2./4),(3./4),(3./18),(1./8),(10./20),(2./6)}; //Add decimal points
    Arrays.sort(fractions); //Sort your array
    double[] removeLowestAndHighest = Arrays.copyOfRange(fractions, 1, fractions.length-1); //returns new array with first and last element removed.    
}

Answer 2

我建议使用List，然后您可以简单地使用.remove（0）、. remove（size-1）

Answer 3

// Create a new array that is 2 smaller than the orriginal.
int[] newArr = new int[arr.length-2];  
// Iterate through the old array, skipping the first and last elements.
for(int i = 0; i < newArr.length; i++)
{
    newArr[i] = arr[i+1];
}

Answer 4

You could convert the array to a list to remove the min/max and then convert back to an array if necessary

You could use Arrays.asList(array) for the conversion

http://docs.oracle.com/javase/7/docs/api/java/util/Arrays.html

Collections has a min and a max method you can use on the list to determine what you need to remove

http://docs.oracle.com/javase/7/docs/api/java/util/Collections.html