题解 | #判断素数个数#

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int start = scanner.nextInt();
        int end = scanner.nextInt();
        method(start,end);
    }

    public static void method(int start, int end) {
        int count=0;

        //write your code here......
        if(start==end){
            if(start<=2){
                count=0;
            }else{
                for(int i=2;i<start;i++){
                    if(start%i==0){
                        count=0;
                    }else{
                        count=1;
                    }
                }
            }
        }else if(start<end){
            count=coluate(start,end);
        }else{
            int temp=start;
            start=end;
            end=temp;
            count=coluate(start,end);
        }
        System.out.println(start+"到"+end+"之间有"+count+"个大于2的素数");
    }
    public static int coluate(int start,int end){
        int count=0;
        int index;
        if(start>2){
            index=start;
        }else{
            index=3;
        }
        while(index<=end){
            boolean isPrime=true;
            for(int i=2;i<index;i++){
                if(index%i==0){
                    isPrime=false;
                }
            }
            if(isPrime==true){
                count++;
            }
            index++;
        }
        return count;
    }
}