java로 소수인지 판별하기

java로 숫자를 입력받아 해당 숫자만큼 case를 입력받아
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/*
* @file            1978/Main.java
* @thinking
print prime number in 4

*
* @exception
*
* @history
*      Version   :  Name     :   Date   :       Modified
*    --------     ------       --------    --------------------
*    VER1.00  :                :  20211115  :        New
*
*/


import java.io.IOException;
import java.util.*;

public class Main {
   public static void main(String[] args) throws IOException {

      Scanner sc = new Scanner(System.in);
          int cnt = sc.nextInt();
      
          int ret =0;
          int flag =0;
          for(int i=0; i<cnt; i++){
          flag =0 ;
          int a = sc.nextInt();
      
          if(a==1){
          flag =3;
          }
          else if(a==2){
          flag =1;
          }
          else{
          for(int j=2;j<a;j++){
         if(a%j==0){
             flag=3;
                 }
          }
          if(flag==0){
       flag=1;
           }
            
          }
      
          if(flag==1){
          ret++;
          }

          }

      
          System.out.println(ret);

   } // end of Main
                
}


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