IntegerArrayUtils.java

package com.dtcc.exams.arrays;

public class IntegerArrayUtils {
    /**
     * @param integerArray - array to have value added to it
     * @param valueToBeAdded - value to be added to the end of the array
     * @return - identical array with one additional element of `valueToBeAdded` at the end of the array
     */
    public static Integer[] add(Integer[] integerArray, Integer valueToBeAdded) {
        int length=integerArray.length;
        Integer[] newArray=new Integer[length+1];
        //copy array integerArray to newArray.
        System.arraycopy(integerArray,0,newArray,0,length);
        newArray[length]=valueToBeAdded;
        return newArray;
    }

    /**
     * @param integerArray - array to be manipulated
     * @param indexToInsertAt - index of the element to be inserted at
     * @param valueToBeInserted - value of the element to be inserted
     * @return `integerArray` with `valueToBeInserted` at index number `indexToInsertAt`
     */

    public static Integer[] replace(Integer[] integerArray, int indexToInsertAt, Integer valueToBeInserted) {
        for(int i=0;i<integerArray.length;i++){
            if(i==indexToInsertAt)
                integerArray[i]=valueToBeInserted;
        }
        return integerArray;
    }

    /**
     * @param integerArray - array to be evaluated
     * @param indexToFetch - index of element to be returned
     * @return element located at `indexToFetch`
     */
    public static Integer get(Integer[] integerArray, Integer indexToFetch) {
        Integer fetchValue = null;
        for(int i=0;i<integerArray.length;i++){
            if(i==indexToFetch)
                fetchValue=integerArray[i];
        }
        return fetchValue;
    }

    /**
     * @param integerArray - array to be evaluated
     * @return identical array with even-values incremented by 1 and odd-values decremented by 1
     */
    public static Integer[] incrementEvenDecrementOdd(Integer[] integerArray) {
        for(int i=0;i<integerArray.length;i++){
            if(integerArray[i]%2==0){ integerArray[i]=integerArray[i]+1; }
            else if(integerArray[i]%2==1) {integerArray[i]=integerArray[i]-1;}
        }
        return integerArray;
    }

    /**
     * @param integerArray - array to be evaluated
     * @return identical array with even-values incremented by 1
     */
    public static Integer[] incrementEven(Integer[] integerArray) {
        for(int i=0;i<integerArray.length;i++)
            if (integerArray[i] % 2 == 0)
                integerArray[i] = integerArray[i] + 1;

        return integerArray;
    }

    /**
     * @param input - array to be evaluated
     * @return identical array with odd-values decremented by 1
     */
    public static Integer[] decrementOdd(Integer[] input) {
        for(int i=0;i<input.length;i++)
            if (input[i] % 2 == 1)
                input[i] = input[i] - 1;

        return input;
    }
}