1.

import java.util.Scanner;

class h{
    public static void main(String[] args){
        int scan = new Scanner(System.in).nextInt();
        if (scan%2 != 0){
            System.out.println(scan+"是奇数");
        }else if (scan%2 ==0&&scan!=0){
            System.out.println(scan+"是偶数");
        }
    }
}

2.

int x = 1;
for (int a=1;a<=5;a++){
    x=x * (a+1);
}
System.out.println(x);

3.

long finalx = 0;
int x=1;
for (int b =1;b<=5;b++) {
    for (int a = 1; a <= b; a++) {
        x = x * (a + 1);
    }
    finalx +=x;
}
 System.out.println(finalx);

4.

result*=i   result=result*i 

1.阶乘题：当int存不下结果时，应使用long类型定义变量