Bag类的接口的实现与测试（课上测试补做）
截图
- 由于截图有一定的的限制就没有吧所有的代码截进去，后面有代码。
代码
package ClassTest;
import java.util.Objects;
/**
* Created by 春旺 on 2017/9/22.
*/
/*
实现接口BagInterface，
声明一个有限长度的T类型的数组用来储存各个类
*/
public class Bag<T> implements BagInterface<T>{
public Object [] arry = new Object[100];
/*
声明一个整形数记录非空的元素
用循环遍历数组不为空时size 加一
为空继续循环
*/
@Override
public int getCurrentSize() {
int size = 0;
for (int i = 0; i < arry.length; i++){
if (arry[i] != null){
size = size + 1;
}
}
return size;
}
/*
遍历数组一发现有非空元素就就变为false 并结束循环
*/
@Override
public boolean isEmpty() {
boolean b = true;
for (int i = 0;i < arry.length;i++){
if (arry[i] != null){
b = false;
break;
}
}
return b;
}
/*
遍历数组，在第一个非空的的数组元素并将其变成输入的元素
*/
@Override
public boolean add(T newEntry) {
boolean b = false;
for (int i = 0;i < arry.length;i++){
if (arry[i] == null){
arry[i] = (Object) newEntry;
b = true;
break;
}
}
return b;
}
/*
随意删除，所以将第一个非空的元素变成null
*/
@Override
public T remove() {
T t = null;
for (int i = 0;i < arry.length;i++){
if (arry[i] != null){
t = (T)arry[i];
arry[i] = null;
break;
}
}
return t ;
}
/*
先查找目标元素，未找到返回false。
for循环遍历数组将所有的目标元素变成
*/
@Override
public boolean remove(T anEntry) {
boolean b = false;
for (int i =0; i < arry.length;i++){
if (anEntry == arry[i]){
arry [i] = null;
b = true;
}
}
return b;
}
/*
删除所有的元素就将原先声明的数组清空
*/
@Override
public void clear() {
for (int i = 0;i< 100;i++) {
arry[i] = null;
}
}
/*遍历数组将目标元素与数组中的元素一一比较
如果相等就进行计数，返回计数后的总的值
*/
@Override
public int getFrequencyOf(T anEntry) {
int number = 0;
for (int i =0; i < arry.length;i++){
if (anEntry == arry[i]){
number ++;
}
}
return number;
}
/* 遍历数组将目标元素与数组中的元素一一比较
只要发现有数组中的元素与目标元素相等就退出循环*/
@Override
public boolean contains(T anEntry) {
boolean b = false;
for (int i =0; i < arry.length;i++){
if (anEntry == arry[i]){
arry [i] = null;
b = true;
break;
}
}
return b;
}
}
- 伪代码已经包含在每个方法的开头。
package ClassTest;
import org.junit.Test;
import static org.junit.Assert.*;
/**
* Created by 春旺 on 2017/9/22.
*/
public class BagTest {
Bag<Student> bag = new Bag<>();
Student s1 = new Student();
@Test
public void getCurrentSize() throws Exception {
Student s1 = new Student();
assertEquals(0,bag.getCurrentSize());
bag.add(s1);
assertEquals(1, bag.getCurrentSize());
}
@Test
public void isEmpty() throws Exception {
assertEquals(true,bag.isEmpty());
Student s1 = new Student();
bag.add(s1);
assertEquals(false,bag.isEmpty());
}
@Test
public void add() throws Exception {
assertEquals(true,bag.add(null));
bag.add(s1);
assertEquals(true,bag.add(s1));
}
@Test
public void remove() throws Exception {
bag.add(s1);
bag.remove();
assertEquals(0,bag.getCurrentSize());
}
@Test
public void remove1() throws Exception {
Student s2 = new Student();
Student s3 = new Student();
Student s4 = new Student();
bag.add(s1); bag.add(s2);
bag.add(s3); bag.add(s4);
bag.add(s1); bag.add(s2);
bag.add(s3); bag.add(s4);
assertEquals(8,bag.getCurrentSize());
bag.remove(s2);
assertEquals(6,bag.getCurrentSize());
}
@Test
public void clear() throws Exception {
for (int i = 0;i<100;i++){
bag.add(s1);
}
assertEquals(100,bag.getCurrentSize());
bag.clear();
assertEquals(0,bag.getCurrentSize());
}
@Test
public void getFrequencyOf() throws Exception {
Student s2 = new Student();
Student s3 = new Student();
for (int i = 0;i < 50;i++){
bag.add(s2);
bag.add(s1);
}
assertEquals(50,bag.getFrequencyOf(s1));
assertEquals(0,bag.getFrequencyOf(s3));
}
@Test
public void contains() throws Exception {
Student s2 = new Student();
Student s3 = new Student();
for (int i = 0;i < 50;i++){
bag.add(s2);
bag.add(s1);
}
assertEquals(true,bag.contains(s2));
assertEquals(false,bag.contains(s3));
}
}
package ClassTest;
/**
2 An interface that describes the operations of a bag of objects.
3
4 */
public interface BagInterface<T>
{
/**
* Gets the current number of entries in this bag.
*
* @return The integer number of entries currently in the bag.
*/
public default int getCurrentSize() {
return 0;
}
/** Sees whether this bag is empty.
@return True if the bag is empty, or false if not. */
public boolean isEmpty();
/** Adds a new entry to this bag.
@param newEntry The object to be added as a new entry.
@return True if the addition is successful, or false if not. */
public boolean add(T newEntry);
/** Removes one unspecified entry from this bag, if possible.
@return Either the removed entry, if the removal
was successful, or null. */
public T remove();
/** Removes one occurrence of a given entry from this bag, if possible.
@param anEntry The entry to be removed.
@return True if the removal was successful, or false if not. */
public boolean remove (T anEntry);
/** Removes all entries from this bag. */
public void clear();
/** Counts the number of times a given entry appears in this bag.
@return The number of times anEntry appears in the bag.
* @param anEntry The entry to be counted.*/
public int getFrequencyOf(T anEntry);
/** Tests whether this bag contains a given entry.
@param anEntry The entry to locate.
@return True if the bag contains anEntry, or false if not. */
public boolean contains(T anEntry);
/** Retrieves all entries that are in this bag.
@return A newly allocated array of all the entries in the bag.
Note: If the bag is empty, the returned array is empty. */
} // end BagInterf
package ClassTest;
/**
* Created by 春旺 on 2017/9/22.
*/
public class Student {
String name;
int id ;
public void student(){
id = 20162324;
name = "春旺";
}
}
- 这个类比较简陋，只是拿来测试就没有写的太详细。
总结
对于这次考试来说我在上课时不知道在做什么，对于老师的意图没有了理解，在课后与同学交流的过程中才知道自己的思想太过于的局限，太过于的执着，在遇到困难时没有想办法绕过去，而是一直纠结于这个问题。