（1）前言
第四次PTA作业：
第四次PTA作业有三道题，两道简单，一道难度较高。一个纯粹的正则表达式的考察。一个时对我们类的设计的考察，一个则是综合的考察
第五次PTA作业：
第五次PTA作业就只有一道题，也即时上次作业的延续。
期中PTA作业：
期中三道题分别考察类的设计，封装和继承，容器类。
（2）设计与分析
第四次PTA作业：
1，3道题目是比较简单的，解决起来难度不大。下面是源码import java.util.Scanner;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner in = new Scanner(System.in);
boolean flag1 = true;
int i = 0;
int total = 0,temp;
String s =in.nextLine();
if(s.equals("end"))
flag1 = false;
while(flag1){
String[] s1 = s.split("\\D");
for(i = 0;i < s1.length;i++) {
if(!s1[i].equals("")) {
temp = Integer.parseInt(s1[i]);
total += temp;
}
}
System.out.println(total);
total = 0;
s =in.nextLine();
if(s.equals("end"))
flag1 = false;
}
}
}
第三题：
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner in = new Scanner(System.in);
BankBusiness account = new BankBusiness();
account.welcome();
account.setaccount(in.next(), in.next());
account.deposit(in.next(), in.nextDouble());
account.withdraw(in.next(), in.nextDouble());
account.withdraw(in.next(), in.nextDouble());
account.withdraw(in.next(), in.nextDouble());
account.welcomeNext();
}
}
class BankBusiness{
public static String bankName = "中国银行";
private String name;
private double balance;
private String password;
void welcome() {
System.out.println(bankName + "欢迎您的到来！");
}
void welcomeNext() {
System.out.println("请收好您的证件和物品，欢迎您下次光临！");
}
public void setaccount(String a ,String b) {
this.name = a;
this.password = b;
this.balance = 0;
}
public void deposit(String c, double d) {
if(this.password .equals(c)) {
this.balance += d;
System.out.println("您的余额有"+balance +"元。");
}
else {
System.out.println("您的密码错误！");
}
}
public void withdraw(String c, double d) {
if(this.password .equals(c)) {
if(this.balance < d) {
System.out.println("您的余额不足！");
}
else {
this.balance -= d;
System.out.println("请取走钞票，您的余额还有" + balance +"元。");
}
}
else {
System.out.println("您的密码错误！");
}
}
}
第五次PTA作业：
在上一次的基础上变成了五边形的计算。下面是五边形部分的源码：
class Pentagon{
Line l = new Line();
boolean is_pen(Point p)
{
if((l.is_xj(p.x1, p.y1, p.x2, p.y2, p.x3, p.y3, p.x4, p.y4) == false)&&(l.is_xj(p.x1, p.y1, p.x2, p.y2, p.x4, p.y4, p.x5, p.y5) == false)&&(l.is_xj(p.x2, p.y2, p.x3, p.y3, p.x4, p.y4, p.x5, p.y5) == false)&&(l.is_xj(p.x2, p.y2, p.x3, p.y3, p.x5, p.y5, p.x1, p.y1) == false)&&(l.is_xj(p.x3, p.y3, p.x4, p.y4, p.x5, p.y5, p.x1, p.y1) == false))
return true;
else
return false;
}
boolean is_pen1(Point p)
{
if((l.is_xj(p.x2, p.y2, p.x3, p.y3, p.x4, p.y4, p.x5, p.y5) == false)&&(l.is_xj(p.x2, p.y2, p.x3, p.y3, p.x5, p.y5, p.x6, p.y6) == false)&&(l.is_xj(p.x3, p.y3, p.x4, p.y4, p.x5, p.y5, p.x6, p.y6) == false)&&(l.is_xj(p.x3, p.y3, p.x4, p.y4, p.x6, p.y6, p.x2, p.y2) == false)&&(l.is_xj(p.x4, p.y4, p.x5, p.y5, p.x6, p.y6, p.x2, p.y2) == false))
return true;
else
return false;
}
boolean AT_pen(Point p)
{
double t1,t2,t3,t4,t5;
t1=(p.x1-p.x3)*(p.y2-p.y3)-(p.x2-p.x3)*(p.y1-p.y3);
t2=(p.x2-p.x4)*(p.y3-p.y4)-(p.x3-p.x4)*(p.y2-p.y4);
t3=(p.x3-p.x5)*(p.y4-p.y5)-(p.x4-p.x5)*(p.y3-p.y5);
t4=(p.x4-p.x1)*(p.y5-p.y1)-(p.x5-p.x1)*(p.y4-p.y1);
t5=(p.x5-p.x2)*(p.y1-p.y2)-(p.x1-p.x2)*(p.y5-p.y2);
if (t1*t2*t3*t4*t5 < 0.0000000001)
return false;
else
return true;
}
public double P_area(Point p)
{
double t1,t2,t3,t4,t5;
t1=(p.x1-p.x3)*(p.y2-p.y3)-(p.x2-p.x3)*(p.y1-p.y3);
t2=(p.x2-p.x4)*(p.y3-p.y4)-(p.x3-p.x4)*(p.y2-p.y4);
t3=(p.x3-p.x5)*(p.y4-p.y5)-(p.x4-p.x5)*(p.y3-p.y5);
t4=(p.x4-p.x1)*(p.y5-p.y1)-(p.x5-p.x1)*(p.y4-p.y1);
t5=(p.x5-p.x2)*(p.y1-p.y2)-(p.x1-p.x2)*(p.y5-p.y2);
double s = 0;
s = (t1+t2+t3+t4+t5);
s = s/8*3;
s = Math.abs(s);
return s;
}
public double P_c(Point p)
{
double c1 = Math.sqrt((Math.pow(p.x1-p.x2, 2)+Math.pow(p.y1-p.y2, 2)));
double c2 = Math.sqrt((Math.pow(p.x2-p.x3, 2)+Math.pow(p.y2-p.y3, 2)));
double c3 = Math.sqrt((Math.pow(p.x1-p.x5, 2)+Math.pow(p.y1-p.y5, 2)));
double c4 = Math.sqrt((Math.pow(p.x3-p.x4, 2)+Math.pow(p.y3-p.y4, 2)));
double c5 = Math.sqrt((Math.pow(p.x4-p.x5, 2)+Math.pow(p.y4-p.y5, 2)));
return c1+c2+c3+c4+c5;
}
}
我也是只实现了一部分的功能，因为初期的类的设计过于粗糙，后面完全把自己绕进去了，所以我后面把自己写的垃圾给删掉了。
期中作业：
期中的题目也是比较简单的。考察的知识点也是基础的。import java.util.Scanner;
import java.text.DecimalFormat;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner in = new Scanner(System.in);
Point p1 = new Point(in.nextDouble(),in.nextDouble());
Point p2 = new Point(in.nextDouble(),in.nextDouble());
Line l = new Line(p1,p2,in.next());
Plane p = new Plane(l.color);
if((p1.getX() > 200 || p1.getX() <= 0) || (p1.getY() > 200 || p1.getY() <= 0) || (p2.getX() > 200 || p2.getX() <= 0) || (p2.getY() > 200 || p2.getY() <= 0))
System.out.println("Wrong Format");
else {
Element e1 = p1;//起点Point
e1.display();
Element e2 = p2;//终点Point
e2.display();
Element e3 = l;//线段
e3.display();
Element e4 = p;//面
e4.display();
}
}
}
class Element{
public void display() {
// TODO Auto-generated method stub
}
}
class Point extends Element{
DecimalFormat df = new DecimalFormat("0.00");
double x;
double y;
public Point(double x, double y) {
super();
this.x = x;
this.y = y;
}
public double getX() {
return x;
}
public void setX(double x) {
this.x = x;
}
public double getY() {
return y;
}
public void setY(double y) {
this.y = y;
}
@Override
public void display(){
System.out.println("("+ df.format(x) + "," + df.format(y) +")");
}
}
class Line extends Element{
DecimalFormat df = new DecimalFormat("0.00");
Point Point1;
Point Point2;
String color;
public Point getPoint1() {
return Point1;
}
public void setPoint1(Point point1) {
Point1 = point1;
}
public Point getPoint2() {
return Point2;
}
public void setPoint2(Point point2) {
Point2 = point2;
}
public Line(Point point1, Point point2, String color) {
super();
Point1 = point1;
Point2 = point2;
this.color = color;
}
double getDistance(Point p1,Point p2) {
return Math.sqrt(Math.pow(p1.getX()-p2.getX(), 2)+Math.pow(p1.getY()-p2.getY(), 2));
}
@Override
public void display() {
if((Point1.getX() > 200 || Point1.getX() <= 0) || (Point1.getY() > 200 || Point1.getY() <= 0) || (Point2.getX() > 200 || Point2.getX() <= 0) || (Point2.getY() > 200 || Point2.getY() <= 0))
System.out.println("Wrong Format");
else {
System.out.println("The line's color is:" + color);
System.out.println("The line's begin point's Coordinate is:");
Point1.display();
System.out.println("The line's end point's Coordinate is:");
Point2.display();
System.out.println("The line's length is:" + df.format(getDistance(Point2, Point1)));
}
}
}
class Plane extends Element{
String color;
public String getColor() {
return color;
}
public void setColor(String color) {
this.color = color;
}
public Plane(String color) {
super();
this.color = color;
}
public void display()
{
System.out.print("The Plane's color is:" + color);
}
}
我的第三题没时间写了，主要是我在第二题时，把display和dispaly拼错了耗费了一个小时的时间在这个上面。
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