软件设计迭代器模式

JAVA和C++常见数据结构迭代器的使用
信1305班共44名同学，每名同学都有姓名，学号和年龄等属性，分别使用JAVA内置迭代器和C++中标准模板库（STL）实现对同学信息的遍历，要求按照学号从小到大和从大到小两种次序输出学生信息。

源码

Java内置迭代器

package rjsj.no18;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

class Student implements Comparable<Student>{

    private String name;
    private int sid;
    private int age;

    public Student(String name, int sid, int age) {
        this.name = name;
        this.sid = sid;
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "姓名='" + name + '\'' +
                ", 学号=" + sid +
                ", 年龄=" + age +
                '}';
    }

    @Override
    public int compareTo(Student o) {
        if (this.sid > o.sid){
            return -1;
        } else if (this.sid < o.sid){
            return 1;
        } else {
            return 0;
        }
    }
}
class IteratorDemo {
    public static void main(String[] args) {
        Student student1 = new Student("张三",20193885,21);
        Student student2 = new Student("李四",20201456,20);
        Student student3 = new Student("王五",20184655,23);
        Student student4 = new Student("赵六",20191242,22);
        Student student5 = new Student("李七",20213256,19);
        List<Student> list = new ArrayList<Student>();
        list.add(student1);list.add(student2);list.add(student3);
        list.add(student4);list.add(student5);
        Collections.sort(list);
        System.out.println("按学号排序输出：");
        Iterator i = list.iterator();
        while (i.hasNext()){
            System.out.println(i.next().toString());
        }
    }
}

C++

#include<iostream>
#include <vector>
#include<algorithm>
using namespace std;
class Student{
public:
     long studentid;
     string name;
     int age;
     string major;
public:
     Student(long studentid, string name, int age, string major) {
        this->studentid = studentid;
        this->name = name;
        this->age = age;
        this->major = major;
    }
    void show(){
        cout<<"姓名: "<<this->name<<"\t学号: "<<this->studentid <<"\t年龄: "<< this->age<< "\t专业: " << this->major<<endl;
    }
};
bool compMax(Student *a,Student *b){
    if (a->studentid> b->studentid)
         return true;
     else
         return false;
}
bool compMin(Student *a,Student *b){
    if (a->studentid< b->studentid)
         return true;
     else
         return false;
}
int main(){
    Student *s1 = new Student(20193288, "张三", 19, "土木");
    Student *s2 = new Student(20193999, "李四", 21, "经管");
    Student *s3 = new Student(20196654, "王五", 22, "软工");
    Student *s4 = new Student(20193367, "赵六", 20, "机械");
    vector<Student*> vec;
    vec.push_back(s1);
    vec.push_back(s2);
    vec.push_back(s3);
    vec.push_back(s4);
    cout<<"按照学号从大到小输出: "<<endl;
    vector<Student*>::iterator it;
    sort(vec.begin(), vec.end(),compMax);
    for(it=vec.begin();it!=vec.end();it++){
        (*it)->show();
    }
    cout<<"-----------------------------------------------------------------"<<endl;
    cout<<"按照学号从小到大输出: "<<endl;
    sort(vec.begin(), vec.end(),compMin);
    for(it=vec.begin();it!=vec.end();it++){
        (*it)->show();
    }
}

运行结果