Program Needed: Perfect Number Program in C language

koool_kid · #1 28-Nov-2004, 11:16

I need a program in simple C language for generating perfect numbers or checking if the entered number is perfect or not. It is needed urgently.

A perfect number is one whose sum of factors is equal to the number, like 6. 6 has 3 factors 1,2,3 when we add 1+2+3 it is equal to 6; hence 6 is perfect number. Likewise 28 is another perfect number. Can I get this program please?

I'm using Borland c++ assembler to compile the programs.

koool_kid · #2 28-Nov-2004, 12:26

Hello again.

I wrote a c program for above question. I don't know how far it's right and I haven't even checked it for myself because I don't have a compiler. It will be great if anyone of you just check this program, thank you.

CPP / C++ / C Code:

  
  #include<stdio.h>
  #include<conio.h>
  main()
  {
  int a,b,c,d;
  printf("Enter a Number");
  scanf("%d", &a);
   a=d;
  for (int i=1;i<=a-1;i++)
  { 
    b=n%i; // im not sure if its b= n%i or b=i%n i cant remember which is the right one
    if(b==0)
      {
         c=c+i;
       }
  }
     if(d==a)
       printf("Entered Number  is perfect number");
     else
       printf("Entered Number is not perfect");
     getch();
}

WaltP · #3 28-Nov-2004, 12:48

I'd recommend the following:
1) Never use urgent in your posts. People are not likely to treat your post as urgent. They'll answer when they read it and some will even avoid it.
2) Use code tags as described in the sticky
3) Download the free borland compiler and test your program Get it here

CPP / C++ / C Code:

a=d;

You've just erased the value you entered. Reverse it.

CPP / C++ / C Code:

b=n%i; // im not sure if its b= n%i or b=i%n

You have it correct.

koool_kid · #4 28-Nov-2004, 12:58

Thanks walt

koool_kid · #5 28-Nov-2004, 14:39

GOTCHA
thats the right program but it is having one typo there "b=n%i" its wrong it shd be "b=a%i" well thanks

koool_kid · #6 28-Nov-2004, 14:40

Here is the correct program for finding a Perfect Number.

CPP / C++ / C Code:

#include<stdio.h>
#include<conio.h>
main()
{
int a,b,c,d;
printf("Enter a Number");
scanf("%d", &a);
d=a;
for (int i=1;i<=a-1;i++)
{ 
b=a%i; // im not sure if its b= n%i or b=i%n i cant remember which is the right one
if(b==0)
{
c=c+i;
}
}
if(d==a)
printf("Entered Number is perfect number");
else
printf("Entered Number is not perfect");
getch();
}

WaltP · #7 28-Nov-2004, 22:17

Quote:

Originally Posted by koool_kid

GOTCHA
thats the right program but it is having one typo there "b=n%i" its wrong it shd be "b=a%i" well thanks

You're right. I didn't look at it that close. Sorry.

Next thing to look at it this tutorial since code tags didn't help at all.

zanyzanny · #8 02-Dec-2005, 02:29

hi
how would you go about modifying this so when you put a number in the nearest perfect number can be found?

Paramesh · #9 02-Dec-2005, 05:24

Hi Zany,

Did you try running that program?
It is wrong!!!!

First, lets try to develop the correct way of finding whether a number is perfect or not:

1. First, get the input from the user. Let that number be num.
2. Create another variable say sum to store the factors one by one.
3. Next, in a loop that varies 'i' from 2 to num/2( Why num/2??? ), check whether num is divisible by i.
4. If it is, then add 'i' to sum. (Why?)
5. After the end of the loop, check whether sum is equal to num.
6. If it is, then the number is a perfect number.
7. Else, the number is not a perfect number...

Now, to your question:

Quote:

Originally Posted by zany

how would you go about modifying this so when you put a number in the nearest perfect number can be found?

You can create a function say int is_perfect(int number) which returns 1 if the number is a perfect number, and 0 if the number is not perfect.
You can use the logic we've developed above.

And, in the main function:

1. Create a variable say j, which is initialized to 0.
2. In a loop, first check whether number + j is a perfect number.
This can be done by using the is_perfect function, like this:
CPP / C++ / C Code:
if(is_perfect(num + i))
3. If it is, then print the perfect number and break the loop.
4. Else, check whether number - j is a perfect number.
5. If it is, then print the perfect number and break the loop.
6. Increment j in the end of the loop, to check for the next number...

Best Regards,

Paramesh.

zanyzanny · #10 02-Dec-2005, 07:47

(the orange, is just trying to get the user within set limits)

Code:

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

void main(void) 
{ 
int number,y=1,high_limit=1000,calculation,a,b=0,c,e; 
do 
  { 
  printf("enter a number between 1 and %d:",high_limit); 
  scanf("%d",&number); 
  if(number>high_limit) 
  printf("your number is too high!\n"); 
  else if(number<y) 
  printf("your number is too low\n"); 
  else 
  printf("\nYour entered number is %d!\n\nThe perfect numbers up to %d are:\n\n",number, number); 
  } 
while (number>high_limit || number<=0); 
system("PAUSE"); 

for(e=number;e>0;e--) 
   { 
   for(a=e-1; a>0; a--) 
             { 
             calculation=e%a; 
             if(calculation==0) 
                                { 
                                "%d\n",a; 
                                b=b+a; 
                                } 
             } 
   if(b==e) 
   printf("\n%d\n\n",e); 
                        { 
                        b=b-b; 
                        } 
                        } 
system("PAUSE"); 
return ; 
}

I don't know where to go from here. (I hope I got the scrolly thing to work).
I think I need to take each perfect number and - the input number then compare, see which is closest.
I was wondering if I could put all the perfect numbers into an array then work with them from that. Thanks for replying so quickly I'm really struggling with this subject. I have limited knowledge

I am quite enjoying it at the same time tho

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Rate This Thread
Rate This Thread:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
C++ Perfect Number Program Help!!!!	lpwilliams21	C++ Forum	4	08-Oct-2006 15:01
Converting a number amount to text	Godzilla	C++ Forum	5	31-Mar-2006 11:38
Help with interactive program, please	nika1p2	C Programming Language	1	09-May-2005 00:22
Anyone can write a program code for this???	chriskan76	C Programming Language	1	19-Oct-2004 20:25

Program Needed: Perfect Number Program in C language

Correct Program for finding Perfect Number

Re: [Program]Urgently Needed Perfect Number Program in C lang

Finding the nearest perfect number in a C program using functions

Re: [Program]Urgently Needed Perfect Number Program in C lang