java - 如何检查整数中有多少个除数以及​​如何将阶乘方程表示为奇数？

Question

所以我的作业告诉我写一个奇数的方程式，当且仅当数字是奇数时，方程式必须是阶乘。

在我的脑海里，结构化是这样的(直到我不知道如何使用阶乘)

import java.util.*;

  public class apple {
public static void main(String args []) {
    Scanner var = new Scanner(System.in);
    int m;
    System.out.println("Type in your first number: ");
    m = var.nextInt();
    if (m==0){ //i don't know if m==0 express the condition to be whole numbers, please tell me which is.
        //here I need to check how many divisors there is for my statement
    }else if //Again, i don't know how to proceed here, i need to place the condition if M is ODD, how?
        //here i need to state (what i guess) the equation of factorial number (in which case, if and only if is odd)

    // and than print the results out. That is all the job it needs to be done.
    }
}
 }

Answer 1

所以如果你有一个奇数，你似乎想打印出一个数的阶乘，如果它是偶数，你想打印出该数的约数。您尚未指定一种表示除数的方法，因此您可以采用以下一种方法:

Scanner var = new Scanner(System.in);
int m;
long x=1; //for the factorial, we want to store in a long to combat data overflow
System.out.println("Type in your first number: ");
m = var.nextInt();
//if the input is odd we calculate its factorial
if (m%2==1){
    for (int i = 1;i<=m;i++)
        x*=i;
    System.out.println(m+"!: "+x);
}
else{
    System.out.println("1 is a divisor for "+m);
    System.out.println("2 is a divisor for "+m);
    if (m%3==0)
        System.out.println("3 is a divisor for "+m);
    //and so on for more divisors of m
}