[the way of programmer training] - 2 Perfect number calculation

【 Preface 】

️ Hello everyone , I am a Catzzz666, It's today The way of programmer training the second day ！

The times are still advancing , We still need to work hard ！️

 

Knowledge points supplement  

Key points of circular nesting ：

1. Whether it's an inner loop or an outer loop , To understand the role of circulation .

2. Clear the relationship between inner circulation and outer circulation .

What is perfect

Perfect number （ Perfect number 、 Complete number ）： All the true factors （ That is, a divisor other than itself ） Of and （ Factor function ）, Exactly equal to it In itself .

give an example ：

28, It has a divisor 1、2、4、7、14、28, Get rid of it 28 Outside , rest 5 Add up the numbers ,1+2+4+7+14=28.

  Title Description

  Particular attention ： This topic is Multiple groups Input .

️ Their thinking ️

A nested loop （while loop （ Realize digital input ） Nest a for loop （ Find all numbers that do not exceed the input number ）,for Nested in the loop again for loop （ Judge whether it is a perfect number ））.

Complete code

#include <stdio.h>

int main()
{
    int num = 0;
    int i = 0;
    while (scanf("%d", &num) != EOF)
    {
        int count = 0;
        for (i = 1; i <= num; i++)
        {
            int j = 0;
            int sum = 0;

            for (j = 1; j <= i / 2; j++)
            {
                if (i % j == 0)
                    sum += j;
            }
            if (sum == i)
                count++;
        }
        printf("%d\n", count);
    }

    return 0;
}

Running results

【 Conclusion 】

Be a person talent Can't support ambition When , Can only read quietly .