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FIND THE PERFECT NUMBER IN C++

What is a perfect number?
"Perfect number is a positive number which sum of all positive divisors excluding that number." 
For example 6 is Perfect Number since divisor of 6 are 1, 2 and 3. Sum of its divisor is
1 + 2+ 3 =6
and  28 is also a Perfect Number
 since 1+ 2 + 4 + 7 + 14= 28
Other perfect numbers: 496, 8128




  1. #include<iostream.h>
  2. #include<conio.h>
  3. void main()                 //Start of main
  4. {
  5.   clrscr();
  6.    int i=1, u=1, sum=0;
  7.    while(i<=500)
  8.  {                                  // start of first loop.

  10.    while(u<=500)
  11.    {                               //start of second loop.
  12.      if(u<i)
  13.      {
  14.       if(i%u==0 )
  15.       sum=sum+u;
  16.      }                          //End of if statement
  17.     
  18.      u++;
  19.    }                           //End of second loop

  21.    if(sum==i)
  22.    {
  23.     cout<<i<<" is a perfect number."<<"\n";
  24.    }

  26.    i++;
  27.    u=1;  sum=0;
  28.  }                             //End of First loop
  29.    getch();
  30.  }                            //End of main

Sample output

6 is a perfect number.
28 is a perfect number.
496 is a perfect number.

Note:
If you want to calculate perfect number within your desire limit simply take a variable and replaced 500 with it.

25 comments:

  1. Randy A MacDonaldJanuary 13, 2012 at 7:55 AM

    In APL: isPerfect←{⍵=+/(⍳⍵-1){(0=⍺|⍵)/⍺}⍵}

    isPerfect 28
    1

    ReplyDelete
  2. Randy A MacDonaldJanuary 13, 2012 at 7:57 AM

    Also...
    {⍵ if isPerfect ¨⍵}⍳500
    6 28 496

    ReplyDelete
  3. Kepler ManuelNovember 6, 2012 at 6:21 AM

    Thanks friend. Great help

    ReplyDelete
  4. AnonymousNovember 27, 2012 at 1:46 AM

    good

    ReplyDelete
  5. UnknownAugust 13, 2013 at 6:55 AM

    very nice.was a great support for me!!!!!

    ReplyDelete
  6. BenzSeptember 18, 2013 at 11:05 AM

    AM NEW DUDE. SO WHERE DO I START?

    ReplyDelete
    Replies
    1. Fahad MunirJune 1, 2014 at 9:02 AM

      You Need To Understand The Basics Of C++ Programming.
      Try To Practice As Much As You Can.
      Practice is Very Important For Your Solid Base to Learn Programming.. Good Luck

      Delete
  7. AnonymousMay 31, 2014 at 11:21 PM

    Fahad bhai: i am new where do i start ?

    ReplyDelete
    Replies
    1. Fahad MunirJune 1, 2014 at 9:02 AM

      Waqas Bhai.
      You Need To Understand The Basics Of C++ Programming.
      Try To Practice As Much As You Can.
      Practice is Very Important For Your Solid Base to Learn Programming.. Good Luck

      Delete
  8. UnknownJune 5, 2014 at 12:01 AM

    #include

    using namespace std;



    int main()
    {
    int num,perfect;
    int per=0;
    cout<<"enter number \n";
    cin>>num;
    int newnum=num;
    for(int i=1;i<=num;i++){
    if(num%i == 0){
    perfect=i;
    cout<<perfect<<endl;
    per=per+perfect;
    }
    }

    if(newnum == per/2){
    cout<<"perfect";
    }else{
    cout<<"not perfect";
    }


    }

    ReplyDelete
  9. UnknownJuly 30, 2014 at 10:59 PM

    This comment has been removed by the author.

    ReplyDelete
  10. UnknownJuly 30, 2014 at 11:00 PM

    A.o.A Fahad ..
    Your website is really really helping. I am a beginner in C++.I have made a more simplest logic for perfect numbers and it works.


    #include
    #include
    using namespace std;
    int main()
    {
    int a,b,c;
    c=0;
    cout<<"Plz enter a number :";
    cin>>b;
    for(a=1;a<b;a++)
    {
    if(b%a==0)

    c=c+a;

    }
    if(c==b)
    cout<<"Yes it is a Perfect number";
    else
    cout<<"No it is not a perfect number";

    getch();

    }

    ReplyDelete
  11. HassiDecember 4, 2015 at 11:40 AM

    what is if and if else statement

    ReplyDelete
  12. UnknownMay 26, 2016 at 11:25 AM

    This comment has been removed by the author.

    ReplyDelete
    Replies
    1. UnknownMay 26, 2016 at 11:27 AM

      This comment has been removed by the author.

      Delete
  13. UnknownJune 23, 2016 at 6:38 AM

    How To Use C++ In Windows7? Becoz in my system windows7 there are not operating c Language & C++ Plz Help...

    ReplyDelete
  14. UnknownOctober 22, 2016 at 12:33 AM

    All the programs are really helpful... but i need more guidance bcuz every time i try to write program, i literally get confused! PLZ HELP ME GET OUT OF IT BCUZ I AM DOING SOFTWARE ENGG! I REALLY NEED HELP

    ReplyDelete
  15. UnknownMay 5, 2017 at 3:12 AM



    Thanks for sharing the very useful info about clanguage and please keep updating........

    ReplyDelete
  16. a todiJune 15, 2017 at 9:48 AM

    hi
    I am a student of class 7and cant understand this.
    please can anyone help me with correcting the following:
    @include<
    #include
    void Main()
    {
    Clrscr();
    Int a=7;
    char section = F;
    cout>>”Hello class”<<a;
    cout<<”\nSection: “<<section<<endline;
    getch()
    }

    ReplyDelete