import java.util.Random;
import java.util.Scanner;

public class Gift {
 public static void main(String[] args) {

  Scanner sc = new Scanner(System.in);
  System.out.println("請您輸入抽獎人數：");
  int n = sc.nextInt();
  Random r1 = new Random();
  System.out.println("幸運兒是："+(r1.nextInt(n)+1));

 }
}

import java.util.Random;
import java.util.Scanner;

public class Gift {
 public static void main(String[] args) {

  Scanner sc = new Scanner(System.in);
  System.out.print("請您輸入抽獎人數：");
  int n = sc.nextInt();
  System.out.print("請您輸入中獎人數：");
  int num;

  // 判斷中獎人數是否符合規(guī)則
  while (true) {
   num = sc.nextInt();
   if (n < num) {
    System.out.println("中獎人數 > 抽獎人數，不符合規(guī)則。");
    System.out.print("\n請重新輸入中獎人數：");

   } else
    break;
  }
  System.out.println("");
  // 創(chuàng)建一個整型數組，來存放抽取的多個幸運兒，來限制不能出現(xiàn)相同序號的幸運兒。
  int[] lucky = new int[num];
  Random r1 = new Random();
  for (int i = 0; i < num; i++) {
   while (true) {
    int luckyMan = r1.nextInt(n) + 1;
    lucky[i] = luckyMan;
    int j = 1;
    if (i == 0) {
     System.out.println("幸運兒是：" + luckyMan);
     break;
    }
    else{
     // 要不等于前面所有的 即 3！=2 && 3！=1 && 3！=0
     if (lucky[i] != lucky[i-1]){
      System.out.println("幸運兒是："+luckyMan);
      break;
     }
    }
   }
  }
 }
}