完数

题目描述

一个数如果恰好等于它的因子之和，这个数就称为"完数"。 例如，6的因子为1、2、3，而6=1+2+3，因此6是"完数"。 编程序找出N之内的所有完数，并按下面格式输出其因子：

输入

N

输出

? its factors are ? ? ?

样例输入

1000

样例输出

6 its factors are 1 2 3 
28 its factors are 1 2 4 7 14 
496 its factors are 1 2 4 8 16 31 62 124 248 

提示

 

来源

#include<stdio.h>

#include<math.h>

void main()

{

    int i,j,k,s1=0,s2=0,l=0,n,m=-1,q,a[100],b[100];

    scanf("%d",&q);

 

    for(n=5; n<=q; n++)

    {

        a[0]=1;

        s1=0;

        s2=0;

        l=0;

        m=-1;

        for(i=2; i<=sqrt(n); i++)

        {

            if(n%i==0)

            {

                j=n/i;

                a[++l]=i;

                b[++m]=j;

                s2+=b[m];

                s1+=a[l];

                //  printf("%d ",i);

            }

        }

        if(s1+s2+a[0]==n)

        {

            if(n==6)

            {

                printf("%d its factors are ",n);

                for(i=0; i<=l; i++)

                    printf("%d ",a[i]);

                for(i=m; i>=0; i--)

                    printf("%d ",b[i]);

 

 

            }

            if(n>6)

            {printf(" ");

                  printf("%d its factors are ",n);

                for(i=0; i<=l; i++)

                    printf("%d ",a[i]);

                for(i=m; i>=0; i--)

                    printf("%d ",b[i]);

 

            }

 

        }

    }

 

}