随机点名测试（随机数 类）

package lianxi;

public class student { //学生类
private string name;
private string gender;
private string grade;
private int age;

public string getname() {
return name;
}

public string getgender() {
return gender;
}

public string getgrade() {
return grade;
}

public int getage() {
return age;
}

public void setname(string name) {
this.name = name;
}

public void setgender(string gender) {
this.gender = gender;
}

public void setgrade(string grade) {
this.grade = grade;
}

public void setage(int age) {
this.age = age;
}

public string tostring() {
return "姓名：" + name + "\t性别：" + gender + "\t班级：" + grade + "\t年龄："
+ age;
}

}

//学生列表（添加学生 随机点名..）

package lianxi;

import java.util.arraylist;
import java.util.scanner;

public class studentlist {
arraylist<student> stlt = new arraylist<student>();

public void addstudent() {
scanner sc = new scanner(system.in);
for (int i = 1; i < 3; i++) {
student st = new student();
system.out.println("添加第" + i + "个学生姓名：");
st.setname(sc.next());
system.out.println("添加第" + i + "个学生性别：");
st.setgender(sc.next());
system.out.println("添加第" + i + "个学生班级：");
st.setgrade(sc.next());
system.out.println("添加第" + i + "个学生年龄：");
st.setage(sc.nextint());
stlt.add(st);
}
}

public void deletestudent(int tr) {
stlt.remove(tr);
}

public arraylist<student> printname() {
return stlt;
}

public string callname() {
/*
* math.random() 方法生成[0,1)范围内的double类型随机数;
* random类中的nextxxxx系列方法生成[0－n)的随机数； math.random() 线程安全，多线程环境能被调用；
* 如无特殊需求，则使用(int)(math.random()*n)的方式生成随机数即可。
*/
return stlt.get((int) (math.random() * stlt.size())).getname()
+ stlt.get((int) (math.random() * stlt.size())).getgender();// 此处学生的每个信息都是随机
// int index = new random().nextint(stlt.size());
// return stlt.get(index);
}
}

//测试

package lianxi;

public class maincallname {
public static void main(string[] args) {
studentlist sl = new studentlist();
sl.addstudent();
system.out.println(sl.printname());
system.out.println(sl.callname());
sl.deletestudent(1);
system.out.println(sl.printname());
system.out.println(sl.callname());
}

}