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Commitefe3acb

Browse files
author
jsquared21
committed
Add Ex_27.10
1 parentcfce324 commitefe3acb

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/*********************************************************************************
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* (Compare MyHashSet and MyArrayList) MyArrayList is defined in Listing 24.3. *
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* Write a program that generates 1000000 random double values between 0 and *
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* 999999 and stores them in a MyArrayList and in a MyHashSet. Generate a list of *
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* 1000000 random double values between 0 and 1999999. For each number in the *
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* list, test if it is in the array list and in the hash set. Run your program to *
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* display the total test time for the array list and for the hash set. *
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*********************************************************************************/
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public class Exercise_27_10 {
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public static void main(String[] args) {
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// Create a MyHashSet
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MySet<Integer> set = new MyHashSet<>();
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set.add();
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}
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}
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/*********************************************************************************
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* (Compare MyHashSet and MyArrayList) MyArrayList is defined in Listing 24.3. *
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* Write a program that generates 1000000 random double values between 0 and *
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* 999999 and stores them in a MyArrayList and in a MyHashSet. Generate a list of *
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* 1000000 random double values between 0 and 999999. For each number in the *
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* list, test if it is in the array list and in the hash set. Run your program to *
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* display the total test time for the array list and for the hash set. *
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*********************************************************************************/
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publicclassExercise_27_10 {
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staticfinalintVALUES =1000000;
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publicstaticvoidmain(String[]args) {
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MySet<Double>set =newMyHashSet<>();// Create a MyHashSet
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MyList<Double>arrayList =newMyArrayList<>();// Create a MyArrayList
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// Generate 1000000 random double values between 0 and 999999
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for (inti =0;i <VALUES;i++) {
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doublerandomDouble =Math.random() *VALUES;
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set.add(randomDouble);
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arrayList.add(randomDouble);
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}
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// Create a list
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double[]list =newdouble[VALUES];
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for (inti =0;i <list.length;i++) {
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list[i] =Math.random() *VALUES;
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}
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System.out.println("Total time for the hash set: " +
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testTimeSet(list,set) +" milliseconds");
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System.out.println("Total time for the array list: " +
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testTimeArray(list,arrayList) +" milliseconds");
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}
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/** Return total test time for the hash set */
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publicstaticlongtestTimeSet(double[]list,MySet<Double>set) {
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longstartTime =System.currentTimeMillis();
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for (inti =0;i <VALUES;i++) {
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set.contains(list[i]);
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}
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returnSystem.currentTimeMillis() -startTime;
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}
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/** Return total test time for the array list */
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publicstaticlongtestTimeArray(double[]list,MyList<Double>array) {
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longstartTime =System.currentTimeMillis();
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for (inti =0;i <VALUES;i++) {
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array.contains(list[i]);
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}
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returnSystem.currentTimeMillis() -startTime;
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}
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}
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publicabstractclassMyAbstractList<E>implementsMyList<E> {
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protectedintsize =0;// The size of the list
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/** Create a default list */
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protectedMyAbstractList() {
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}
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/** Create a list from an array of objects */
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protectedMyAbstractList(E[]objects) {
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for (inti =0;i <objects.length;i++)
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add(objects[i]);
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}
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@Override/** Add a new element at the end of this list */
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publicvoidadd(Ee) {
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add(size,e);
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}
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@Override/** Return true if this list doen't contain any elements */
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publicbooleanisEmpty() {
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returnsize ==0;
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}
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@Override/** Return the number of elements in this list */
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publicintsize() {
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returnsize;
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}
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@Override/** Remove the first occurence of the element e
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* from this list. Shift any subsequent elements to the left.
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* Return true if the element is removed. */
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publicbooleanremove(Ee) {
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if (indexOf(e) >=0) {
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remove(indexOf(e));
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returntrue;
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}
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else
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returnfalse;
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}
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}
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publicclassMyArrayList<E>extendsMyAbstractList<E> {
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publicstaticfinalintINITIAL_CAPACITY =16;
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privateE[]data = (E[])newObject[INITIAL_CAPACITY];
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/** Create a default list */
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publicMyArrayList() {
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}
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/** Create a list from an array of objects */
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publicMyArrayList(E[]objects) {
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for (inti =0;i <objects.length;i++)
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add(objects[i]);
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}
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@Override/** Add a new element at the specified index */
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publicvoidadd(intindex,Ee) {
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ensureCapacity();
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// Move the elements to the right after the speciied index
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for (inti =size -1;i >=index;i--)
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data[i +1] =data[i];
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// Insert new element to data[index]
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data[index] =e;
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// Increase size by 1
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size++;
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}
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/** Create a new larger array, double the current size + 1 */
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privatevoidensureCapacity() {
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if (size >=data.length) {
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E[]newData = (E[])(newObject[size *2 +1]);
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System.arraycopy(data,0,newData,0,size);
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data =newData;
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}
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}
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@Override/** Clear the list */
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publicvoidclear() {
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data = (E[])newObject[INITIAL_CAPACITY];
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size =0;
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}
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@Override/** Return true if this list contains the element */
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publicbooleancontains(Ee) {
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for (inti =0;i <size;i++)
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if (e.equals(data[i]))returntrue;
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returnfalse;
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}
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@Override/** Return the element at the specified index */
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publicEget(intindex) {
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checkIndex(index);
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returndata[index];
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}
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privatevoidcheckIndex(intindex) {
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if (index <0 ||index >=size)
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thrownewIndexOutOfBoundsException("index" +index +" out of bounds");
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}
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@Override/** Return the index of the first matching element
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*in this list. Return -1 if no match. */
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publicintindexOf(Ee) {
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for (inti =0;i <size;i++)
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if (e.equals(data[i]))returni;
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return -1;
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}
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@Override/** Return the index of the last matching element
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*in this list. Return -1 if no match. */
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publicintlastIndexOf(Ee) {
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for (inti =size -1;i >=0;i--)
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if (e.equals(data[i]))returni;
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return -1;
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}
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@Override/** Remove the element at the specified position
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*in this list. Shift any subsequent elements to the left.
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*Return the element that was removed from the list. */
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publicEremove(intindex) {
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checkIndex(index);
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Ee =data[index];
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// Shift data to the left
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for (intj =index;j <size -1;j++)
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data[j] =data[j +1];
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data[size -1] =null;// This element is now null
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// Decrement size
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size--;
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returne;
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}
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@Override/** Replace the element at the specified position
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*in this list with the specified element. */
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publicEset(intindex,Ee) {
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checkIndex(index);
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Eold =data[index];
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data[index] =e;
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returnold;
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}
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@Override
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publicStringtoString() {
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StringBuilderresult =newStringBuilder("[");
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for (inti =0;i <size;i++) {
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result.append(data[i]);
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if (i <size -1)result.append(", ");
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}
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returnresult.toString() +"]";
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}
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/** Trims the capacity to current size */
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publicvoidtrimToSize() {
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if (size !=data.length) {
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E[]newData = (E[])(newObject[size]);
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System.arraycopy(data,0,newData,0,size);
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data =newData;
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}// If size == capacity, no need to trim
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}
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@Override/** Override iterator() defined in Iterable */
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publicjava.util.Iterator<E>iterator() {
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returnnewArrayListIterator();
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}
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privateclassArrayListIterator
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implementsjava.util.Iterator<E> {
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privateintcurrent =0;// Current index
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@Override
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publicbooleanhasNext() {
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return (current <size);
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}
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@Override
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publicEnext() {
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returndata[current++];
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}
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@Override
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publicvoidremove() {
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MyArrayList.this.remove(current);
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}
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}
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}
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