Counting prime divisors of a number..

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i just trying to count the prime divisors of a number....but getting error in counting help please.......

[edit]Code

C++

# include <stdio.h>
# include <math.h>
#include
#include <iostream>
using namespace std;

long long i=0,a=0;
//long long count=0;
bool prime(int n)
{
	for(int i=2; i<n;>    {
		if(n%i==0)
			return 0;
	}
	return 1;
}

int divisors(long long n)
{
	int check=0;
	for(i=n/10; i    {
		bool p=prime(i);     //checking the value of i is prime or not
		if(p==1)
		{
			if(n%i==0)      //counting prime divisors for current number,here i am getting error
			{
				check++;
				a=i;
			}
		}
	}
	return check;     //returning the number of prime divisors of current number
}

int main()
{
	string s;
	while(cin>>s)        //taking a at most 14 digit number
	{
		int len=s.size(),count=0;
		long long number=0;
		for(int i=0; i<len;>        {
			int digit=s[i]-'0';
			number*=10;
			number+=digit;          //converting into number
			count+=divisors(number);//counting the prime divisors of the current number
		}

		if(count>1)
			cout<<a<<endl;
		else
			cout<<"-1\n";
	}
	return 0;
}

block added - OriginalGriff[/edit]

Posted 28-Apr-16 0:27am

Member 12270086

Updated 28-Apr-16 3:22am

Patrice T

v3

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Comments

Patrice T 28-Apr-16 6:38am

What error ? Where ?

Patrice T 28-Apr-16 9:25am

How many prime divisors do you expect for 36 ?

Philippe Mori 28-Apr-16 12:26pm

Fix typos in your code.

Philippe Mori 28-Apr-16 12:34pm

What are you trying to do with multiplication and division by 10?

Patrice T 28-Apr-16 14:01pm

Manual conversion from string to int.

Philippe Mori 28-Apr-16 14:34pm

Then why divisors is called Inside the loop? The question was more for OP to explain what he wants to do in more details.

Patrice T 28-Apr-16 14:38pm

Just another Bug.
The code do not even compile.

3 solutions

Solution 3

You should learn to use the debugger as soon as possible. Rather than guessing what your code is doing, It is time to see your code executing and ensuring that it does what you expect.

The debugger allow you to follow the execution line by line, inspect variables and you will see that there is a point where it stop doing what you expect.
Debugger - Wikipedia, the free encyclopedia[^]
Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]
http://docs.oracle.com/javase/7/docs/technotes/tools/windows/jdb.html[^]
https://www.jetbrains.com/idea/help/debugging-your-first-java-application.html[^]

Once your program compile, you will absolutely need to run it on debugger to understand what it is doing.
Run the program line by line and inspect variables to see what each line is doing.

Posted 28-Apr-16 1:56am

Patrice T

Updated 28-Apr-16 16:53pm

v4

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OriginalGriff · Accepted Answer · 2016-04-28T00:41:00

You're getting errors long before you start running the code - that won;t compile - which is probably why you are "getting error".

Start by looking at the compiler output - in most IDE's if you double click an error message it will take you to the appropriate line.
The obvious ones to start with are:

C++

# include <stdio.h>
# include <math.h>

You shouldn;t have a space between '#' and 'include'

C++

#include

Doesn't load anything, so it will cause problems. Get rid of it.

C#

long long i=0,a=0;

What is a "long long"? You only need the type name once.

C#

for(int i=2; i<n;>    {

What happened to the increment? and the close bracket?
Try:

C#

for(int i=2; i<n; i++)    {

There will be others, but I'm not a compiler - so use yours and read the error messages!

Other things you should think about:
Pick a bracketing style and stick to it: mixing 1TB with K&R in a trivial app is just silly because it makes it hard for you to read, never mind anyone else.
So

C#

bool myFunction()
{
   for (...) {
      statement;
   }
}

doesn't help you.
Stick to K&R:

C++

bool myFunction()
{
   for (...) 
   {
      statement;
   }
}

Or Whitesmiths:

C++

bool myFunction()
   {
   for (...) 
      {
      statement;
      }
   }

Don't try to use 1TB until you are well and truly familiar with the language itself.

CPallini · Accepted Answer · 2016-04-28T01:03:00

try

C++

 #include <stdio.h>
 #include <math.h>
 #include <iostream>
using namespace std;


bool prime(long long n)
{
  for(int i=2; i<n; ++i)
  {
    if (n % i == 0 ) return false;
  }
  return true;
}

int divisors(long long n)
{
  int check =  0;

  for (i=2; i<n; ++i)
  {
    if ( (n% i) == 0)
    {
      cout << "divisor " << i << " is ";
      if (prime(i))
      {
        cout << "prime ";
        check++;
      }
      else
        cout << "not prime";
      cout << endl;
    }
  }
  return check;
}

int main()
{
    long long number;

    cout << "please enter a number: " << endl;
    cin >> number;

    cout << "there are " << divisors(number) << " prime divisors of " << number << endl;
    return 0;
}

Counting prime divisors of a number..

3 solutions

Solution 1

Solution 3

Solution 2

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