ARMSTRONG NUMBERS. Problem with my program -- the loop works till 149 but creates problem as soon as it gets to 150.

Question

1.00/5 (1 vote)

See more:

An Armstrong number is a n digit number, which is equal to the sum of the nth powers of its digits.
So, i have to print Armstrong numbers between 1 and 500. there are 12 of them in total between the range.

the program i have written, it actually was not printing Armstrong numbers over 9. so i decided to test it by printing the numbers that i get from the 'sum' mentioned above.
this is how i found out that the loop was working above 149. Whenever it reaches 150, the program somehow subtracts 1 from the 'sum'. ~~PLEASE HELP AS I HAVE TO SUBMIT IT IN A COUPLE OF DAYS.~~

What I have tried:

C++

#include <iostream>
#include <math.h>

using namespace std;

int main()
{
    int di;
    for(int a = 1, b = a, c = a, sum = 0, digi = 0;a <= 150;a++, b = a, digi = 0, c = a, sum = 0)
    {
        for(b;b != 0;b /= 10, digi++);
        do
        {
            di = c % 10;
            sum += pow(di, digi);
            c /= 10;
        }while(c != 0);
        cout << sum << " ";
        // if(sum == a) cout << sc << " ";
    }
}

Posted 18-Aug-17 23:04pm

Member 13368218

Updated 19-Aug-17 1:23am

Richard MacCutchan

v2

Add a Solution

Comments

Richard MacCutchan 19-Aug-17 5:23am

Suggestions:
- Start by giving your variables meaningful names, so we can understand the purpose of each one.
- Next take out all those extra expressions from your for statements so we can understand what they are supposed to be doing.
- Then add some comments so the code is easier to understand.

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Patrice T · Answer 1 · 2017-08-19T00:27:00

Quote:
So, i have to print Armstrong numbers between 1 and 500.

There is no way an integer variable can hold so much digits. An int can't hold much more than 10 digits.
You should study the different C data types.
Oops, made a mistake between the values and number of digits

C++

for(int a = 1, b = a, c = a, sum = 0, digi = 0;a <= 150;a++, b = a, digi = 0, c = a, sum = 0)

There is no point to type such code, there is no gain, it only make it more difficult to read and to understand.
Any gain in number of lines of code is at the expense of readability.

[Update]
Advice: make your code easier to read.
Then use the debugger to see your code perform, it will help you to understand why it go wrong.

There is a tool that allow you to see what your code is doing, its name is debugger. It is also a great learning tool because it show you reality and you can see which expectation match reality.
When you don't understand what your code is doing or why it does what it does, the answer is debugger.
Use the debugger to see what your code is doing. Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.

Debugger - Wikipedia, the free encyclopedia[^]

Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]
Basic Debugging with Visual Studio 2010 - YouTube[^]
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't find bugs, it just help you to. When the code don't do what is expected, you are close to a bug.

RAMASWAMY EKAMBARAM · Answer 2 · 2017-08-19T01:23:00

You can use sprintf() to convert each value (from 1 to 500) to a displayable string. The string length will be the number of digits (i.e. exponent) and subtracting '0' from each char in the array (using a loop) will give you the digit value and you already have the exponent.
Coding this way should be easier and you should be able to 'submit in a couple of ~~days~~ hours'.

ARMSTRONG NUMBERS. Problem with my program -- the loop works till 149 but creates problem as soon as it gets to 150.

2 solutions

Solution 1

Solution 2

Add your solution here

Preview 0