ArrayList

package heima;
import java.util.ArrayList;
//import javax.sound.sampled.Line;
import java.util.Scanner;

public class a1 {
    public static void main(String[] args) {
    ArrayListarray=new ArrayList();
        array.add("hello");
        array.add("word");
        array.add("java");
        array.add("k");
        array.add(1,"javase");
        array.add(3,"javase");
        System.out.println(array);

    }



}

package heima;
import java.util.ArrayList;
//import javax.sound.sampled.Line;
import java.util.Scanner;

public class a1 {
    public static void main(String[] args) {
    ArrayListarray=new ArrayList();
        array.add("hello");
        array.add("world");
        array.add("java");
//        System.out.println(array.remove("world"));
//        System.out.println(array.remove("javaee"));
//        System.out.println(array.remove(1));
  // System.out.println(array.set(1,"修改"));
       // System.out.println(array.get(0));
       // System.out.println(array.size());

        System.out.println(array);

    }



}

遍历String

package heima;
import java.util.ArrayList;
//import javax.sound.sampled.Line;
import java.util.Scanner;

public class a1 {
    public static void main(String[] args) {
   ArrayListarray=new ArrayList();
   array.add("刘正风1");
   array.add("刘正风2");

   for(String k:array){
       System.out.println(k);
   }

    }

}

遍历学生类

（1）

package heima;

public class Student {

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

    public void setName(String name) {
        this.name = name;
    }
    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

package heima;
import java.util.ArrayList;
//import javax.sound.sampled.Line;
import java.util.Scanner;

public class a1 {
    public static void main(String[] args) {
ArrayListarray=new ArrayList();
Student s1=new Student("为对方",23);
Student s2=new Student("Wdq",23);
Student s3=new Student("权威的",44);
array.add(s1);
array.add(s2);
array.add(s3);
    for(int i=0;i<3;i++){
        Student s=array.get(i);
        System.out.println(s.getName()+","+s.getAge());
    }

    }

}

（2)

package heima;

public class Student {

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

    public void setName(String name) {
        this.name = name;
    }
    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

package heima;
import java.util.ArrayList;
//import javax.sound.sampled.Line;
import java.util.Scanner;

public class a1 {
    public static void main(String[] args) {
        ArrayListarray=new ArrayList();
add(array);
add(array);
add(array);
for(int i=0;i< array.size();i++){
    Student s=array.get(i);
    System.out.println(s.getName()+","+s.getAge());
}


    }
    public static void add(ArrayListarray){
        Scanner k=new Scanner(System.in);
        System.out.println("姓名");
        String name=k.nextLine();
        System.out.println("年龄");
        int age=k.nextInt();
        Student s=new Student();
        s.setName(name);
        s.setAge(age);
        array.add(s);
    }
}