java - 添加多个用户输入的因素

Question

我正在尝试添加用户提供的数字的所有因子。例如，如果用户输入 5，则输出应为:“5 的因数之和为 6”。 我不知道如何添加这些数字。这是我尝试过的:

int i = 1;
int count = 0;
int sum = 0;
while(i <= num) 
{
   sum = i + 1;
   if(num % i == 0)
   {
       System.out.println(i + " is a factor of "+num+".");
       count++;
   }

    i++;
}  

 System.out.println(num+" has "+count+" factors.");
 System.out.println("The sum of all of the factors of "+num+" is "+sum);

Answer 1

您的代码中存在逻辑错误。基本上，您每次通过循环都会重置总和，而不是将这些因子累积起来以获得运行总计。因此，在循环的最后一次迭代中，您将得到最后检查的数字加一。要修复该错误，请删除此行:

sum = i + 1;

并在 if 条件中添加此行:

sum += i;

代码应如下所示:

int i = 1;
int count = 0;
int sum = 0;
while(i <= num) 
{
   if(num % i == 0)
   {
       System.out.println(i + " is a factor of "+num+".");
       count++;
       sum += i;
   }
   i++;
}  

System.out.println(num+" has "+count+" factors.");
System.out.println("The sum of all of the factors of "+num+" is "+sum);        

我刚刚验证了 n=5 的输出是:

1 is a factor of 5.
5 is a factor of 5.
5 has 2 factors.
The sum of all of the factors of 5 is 6

但是 5 是质数。这是一个包含更多因素的更有趣的示例:n=8:

1 is a factor of 8.
2 is a factor of 8.
4 is a factor of 8.
8 is a factor of 8.
8 has 4 factors.
The sum of all of the factors of 8 is 15

注意:您的算法可以优化。提示:当您找到一个因子时，您可以通过将输入的数字除以它来轻松确定另一个因子。我将其余的优化留给您作为练习。享受吧!