燕山楠Homework 0

数据结构 JAVA

程序源码

一些尝试：
1、学习使用JAVA的输入语句，减少程序修改次数。
2、throw new IllegalArgumentException("")可以自定义报错显示+直接终止程序。

import java.util.Scanner;
public class Hw1_12
{
  static class Set<E>
  {
    final int Mxsize=100;
    E[] data;
    int size;
    public Set()
    {
      data=(E[])new Object[Mxsize];
      size=0;
    }
    public int getsize()
    {
      return size;
    }
    public E get(int i)
    {
      if(i<0||i>=size) 
        throw new IllegalArgumentException("failing get: I is not in the right range!");
      return (E)data[i];
    }
    public boolean IsIn(E e)
    {
      for(int i=0;i<size;i++)
        if(data[i]==e) return true;
      return false;
    }
    public boolean add(E e)
    {
      if(IsIn(e)||size==Mxsize) return false;
      else
      {
        data[size]=e;
        size++;
        return true;
      }
    }
    public boolean delete(E e)
    {
      int i=0;
      while(i<size&&data[i]!=e) i++;
      if(i>=size) return false;
      for(int j=i+1;j<size;j++) data[j-1]=data[j];
      size--;
      return true;
    }
    public void display()
    {
      for(int i=0;i<size;i++)
        if(i==0) System.out.print(data[i]);
        else System.out.print(" "+data[i]);
      System.out.println();
    }
  }
  static class TwoSet<E>
  {
    public Set<E> Union(Set<E> s1,Set<E> s2)
    {
      Set<E> s3=new Set<E>();
      for(int i=0;i<s1.getsize();i++) s3.add(s1.get(i));
      for(int i=0;i<s2.getsize();i++) 
        if(!s1.IsIn(s2.get(i))) s3.add(s2.get(i));
      return s3;
    }
    public Set<E> Intersection(Set<E> s1,Set<E> s2)
    {
      Set<E> s3=new Set<E>();
      for(int i=0;i<s1.getsize();i++) 
        if(s2.IsIn(s1.get(i))) s3.add(s1.get(i));
      return s3;
    }
    public Set<E> Difference(Set<E> s1,Set<E> s2)
    {
      Set<E> s3=new Set<E>();
      for(int i=0;i<s1.getsize();i++) 
        if(!s2.IsIn(s1.get(i))) s3.add(s1.get(i));
      return s3;
    }
  }
  public static void main(String[] args)
  {
    Set<Integer> s1,s2,s3,s4,s5;
    TwoSet<Integer> t=new TwoSet<Integer>();
    s1=new Set<Integer>();
    Scanner in=new Scanner(System.in);
    System.out.println("Please enter the size of Set s1:  ");
    int n=in.nextInt();
    System.out.println("Please enter the elements of Set s1:  ");
    while(n>0) {s1.add(in.nextInt());n--;}
    s2=new Set<Integer>();
    System.out.println("Please enter the size of Set s2:  ");
    n=in.nextInt();
    System.out.println("Please enter the elements of Set s2:  ");
    while(n>0) {s2.add(in.nextInt());n--;}
    s3=t.Union(s1,s2);
    System.out.println("s3 is the union of s1 and s2!");
    System.out.print("Set s3:  ");s3.display();
    s4=t.Difference(s1,s2);
    System.out.println("s4 is the difference set of s1 and s2!");
    System.out.print("Set s4:  ");s4.display();
    System.out.println("s5 is the intersection of s1 and s2!");
    s5=t.Intersection(s1,s2);
    System.out.print("Set s5:  ");s5.display();
    s1.get(5);//看看自己写的边界检查语句效果怎么样
  }
}