Perfect Numbers

Perfect Numbers

Let's take a perfect number 10. We write numbers into an array from 1 to 10 in the way that odd numbers from left to write till the middle and even numbers from end to middle. Then we start to put each number into the place where belongs. If every number goes its correct place, we say that 10 is a perfect number.

The Algorithm

C Source Code

#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
#include<time.h>

int Dizi_muk(long n)
{
unsigned int i, j, k, t, m, a[20000];

for(i=5;i<n;i++)
{
    k = 1;
    for(j=0;j<i;j++)
    {
      if( (k & 1) == 1 ) // sayy tek
            a[(j+1)/2] = k;
       else  // sayy çift
            a[i-(j+1)/2] = k;
      k++;
    }
    k = 2;
    t = i;
    j = 1;
    while(t != 2)
    {
      m = 0;
      while((a[m] != t) && (m<i))
            m++;
      a[t-1] = a[m];
      t = m+1;
      j++;
    }
    a[t-1] = 2;
    j++;
    if(j == i)
      printf("%d is a perfect number\n", i);
}
return 0;
}
void main(void)
{
long n;
double time1, time2;
clock_t start, end;
clrscr();
printf("Perfect numbers till(max number): ");scanf("%ld",&n);
start = clock();
Dizi_muk(n);
end = clock();
time1 = (double)(end - start) / CLK_TCK;
printf("Time elapsed: %5.4f seconds\n", time1);
getch();
}

Perfect Numbers from 5 to 999

6	159	355	586	792
7	174	360	594	804
10	175	372	607	810
12	180	376	612	811
15	184	379	615	819
19	187	387	616	832
24	190	394	619	834
27	192	399	630	835
30	195	411	639	847
31	210	412	640	867
34	211	414	642	871
36	222	415	646	874
40	231	420	651	880
42	232	427	652	892
51	234	430	654	894
52	240	432	660	912
54	244	439	684	924
66	246	442	687	931
70	252	444	691	934
75	255	454	714	936
82	262	471	720	939
84	271	474	724	940
87	274	484	726	951
90	279	492	727	954
91	282	496	742	966
96	294	510	744	975
99	300	516	747	976
100	304	520	750	987
106	307	531	756	990
114	310	532	762	994
120	324	544	766	999
132	327	546	772
135	330	555	775
136	331	559	780
147	339	562	784

There are 175 perfect numbers.

Elapsed time to generate perfect numbers till 1000 is 0,934 seconds using Celeron 500 MHz CPU.