Thread: whats wrong with my code ..i m trying to print armstrong numbers from 1 to 1000 ..

Code:

#include<conio.h>
#include<stdio.h>
#include<math.h>
int main()
{
int j,number,i,storenumber,sum,power=0,remainder;
/* number is the list of numbers generated from 1 to 1000, storenumber stores the value of number while its being edited for other purpose,power is the individual digits raised to power equal to total digits in the number */
for(number=1;number<1001;number++)
{
storenumber=number;
i=0;
  while(number>0)
 {
 number=number/10;
 i=i+1;
// i simply extracts the number of digits in the given number 
 }
number=storenumber;
sum=0;
  for(j=1;j<=i;j++)
  {
  remainder=number%10;
  power=pow(remainder,i);
  number=number/10;
  sum=sum+power;
  }
//runs the above loop for as many times as the number of digits in the number
number=storenumber;
    if(sum == number)
   {
   printf("%d is an armstrong number \n",sum);
    }
          
}
getch();
}

i dont know whats wrong with this code all it prints is that 1 is an armstrong number...pls sum1 point out the mistake

I don't have the time to go over your code, but let me say that it is more likely you will get some help if your program is easy to read (i.e., you need to use code tags to preserve your indentation). You can read about how to use code tags here.

Code:

#include<conio.h>
#include<stdio.h>
#include<math.h>
int main()
{
    int j, n, i = 0, k, sum = 0, y = 0, r;
    for (n = 1; n < 1001; n++) {
        k = n;
        while (n > 0) {
            n = n / 10;
            i = i + 1;
// i simply extracts the number of digits in the given number
        }
        n = k;
        for (j = 1; j <= i; j++) {
            r = n % 10;
            y = pow(r, i);
            n = n / 10;
            sum = sum + y;
        }
//runs the above loop for as many times as the number of digits in the number
        n = k;
        if (sum == n) {
            printf("%d is an armtrong number \n", sum);
        } else {
            printf(" ");
        }

    }
    getch();
}

Also, try to use variable names that have some meaning. Nobody is going to read through a cryptic program using all the alphabet as different variables. i,j,k are ok for loops but that should be about it.

Also, your sum variable should be initialized to 0 before computing the sum for each number.

There is a lot of inefficiency in this:

Code:

number=storenumber;
sum=0;
  for(j=1;j<=i;j++)
  {
  remainder=number%10;
  power=pow(remainder,i);
  number=number/10;
  sum=sum+power;
  }

Remainder, i, power, and number are always the same, so how about:

Code:

  remainder=number%10;
  power=pow(remainder,i);
  number=number/10;
  sum = power*i;

No need for the loop at all. Also the use of storenumber and number is silly. Just copy it into some other variable and use that instread of saving it in a different variable and resetting it.

However, the problem is that your formula for Armstrong numbers is wrong, as hopefully is clearer now I have simplified your operations.

I'm really sorry, I must have been ignoring this line in my analysis:

Code:

  number=number/10;

Which does make the loop purposeful and my reduction of it incorrect! (In fact, I wrote that post, then deleted it, then posted it again -- presumably I noticed my mistake and then stupidly forgot it...)

Anyway, I didn't mean you don't need a loop, I meant I thought the loop you were using was incorrect, since it didn't do much (but that was my mistake).

It could still be incorrect for calculating the armstrong number although it is probably close. I would do this:

Code:

        if (sum == n) {
            printf("%d is an armtrong number \n", sum);
        } else {
            printf("n = %d  but sum = %d\n",n,sum);
        }

This will enable you to see (if you have a list of the correct armstrong numbers) where you are going wrong and hopefully, why.

Originally Posted by jaikoolwal

@MK27-thnx for the help ...i appreciate it

well now all of my code is working and it is also printing all the armstrong numbers except for 153...i wonder why...ny suggestions ny1??

Did you try adding that printf? Check what it says the sum for is when n =153. Obviously you are very close.