Scanner、Random、ArrayList的基礎編程練習題

標籤：個學生   name   偶數   rgs   ++   for   system.in   static   資料   

產生6個1~33之間的隨機整數,添加到集合,並遍曆

package ArrayList;import java.util.ArrayList;import java.util.Random;/** 思路* 6個--->6.fori* 1~33之間--->xxx.nextInt(33)+1;* 隨機整數--->Random xxx = new Random();* 添加到集合--->ArrayList<Integer> xxx = new ArrayList<>(); list.add();* 遍曆--->xxx.fori;--->list.get(索引);** */public class ArrayList_4 {    public static void main(String[] args) {        Random r = new Random();        ArrayList<Integer> list = new ArrayList<>();        for (int i = 0; i < 6; i++) {            int num = r.nextInt(33)+1;            list.add(num);        }        System.out.println(list);        for (int i = 0; i < list.size(); i++) {            System.out.print(list.get(i)+" ");        }    }}

自訂4個學生對象,添加到集合,並遍曆

package ArrayList;import Class_Objiect.Student;import java.util.ArrayList;/** 思路* 自訂4個學生對象--->Student one = new Student();*                   Student two = new Student();*                   Student three = new Student();*                   Student four = new Student();* 添加到集合--->ArrayList<Student> list = new ArrayList<>(); &  list.add(內容);* 遍曆--->list.fori--->list.get(index);* */public class ArrayList_5 {    public static void main(String[] args) {        ArrayList<Student> list = new ArrayList<Student>();        Student one = new Student("Andy",18);        Student two = new Student("Bill",19);        Student three = new Student("Lily",32);        Student four = new Student("Jane",12);        list.add(one);        list.add(two);        list.add(three);        list.add(four);        for (int i = 0; i < list.size(); i++) {            System.out.println("姓名："+list.get(i).getName()+"  "+"年齡："+list.get(i).getAge()+"歲");        }    }}

定義以指定格式列印集合的方法(ArrayList類型作為參數)，使用{}擴起集合，使用@分隔每個元素。格式參照 {元素@元素@元素}。

package ArrayList;import java.util.ArrayList;/** 思路* ArrayList<資料類型> xxx = new ArrayLIstanbul<>();* */public class ArrayList_6 {    public static void main(String[] args) {        //建立集合        ArrayList<Integer> list = new ArrayList<>();        //添加元素        list.add(1);        list.add(3);        list.add(5);        list.add(7);        //調用方法        print(list);    }    public static void print(ArrayList<Integer> list) {        System.out.print("{");//列印  {        for (int i = 0; i < list.size(); i++) {            if (i == list.size() - 1) {                System.out.print(list.get(i));//列印數字            } else {                System.out.print(list.get(i) + "@");//列印  "數字@"            }        }        System.out.println("}");//列印 }    }}

定義1~30之間（包括1和30），所有偶數元素集合的方法(ArrayList類型作為傳回值)

package ArrayList;import java.util.ArrayList;import java.util.Random;/** 思路* 1-30之間--->xxx.nextInt(30)+1；* 所有偶數元素--->if（i%2==0){偶數}* 方法 public static String method(ArrayList<String> list)* */public class ArrayList_7 {    public static void main(String[] args) {        ArrayList<Integer> list = new ArrayList<>();        for (int i = 1; i <=30; i++) {            if(i%2==0){                list.add(i);            }        }        System.out.println(list);    } }

遊戲開始時，會隨機產生一個1-100之間的整數 number 。玩家猜測一個數字guessNumber ,會與 number 作比 較，系統提示大了或者小了，直到玩家猜中，遊戲結束

package Random;/*思路隨機--->Random r = new Random();1~100-->int number = r.nextInt(100)+1;猜測 --->Scanner sc = new Scanner(System.in);--->int guessNumber = sc.nextInt();if(guessNumber>number){大了}if(guessNumber<number){小了}if(guessNumber==number){猜對了}guessNumber應該是一個迴圈；* */import java.util.Random;import java.util.Scanner;public class Random_4 {    public static void main(String[] args) {        Random r = new Random();        Scanner sc = new Scanner(System.in);        int number =r.nextInt(100)+1;        System.out.println("請輸入：");        for (int i = 0; i <100 ; i++) {            int guessNumber = sc.nextInt();          if(guessNumber>number){              System.out.println("大了");          }else if(guessNumber<number){              System.out.println("小了");            }else if(guessNumber==number){              System.out.println("猜對了");                }            }        }    }

Scanner、Random、ArrayList的基礎編程練習題