Time or Fault?

[Akshit]

for(b;b<10000000;b+=2)
	{
		if(b%3==0)
			b+=2;
		if(checkprime(b))
			a++;
	}

How much time will this loop takes?
Because for me its taking too long.
or is it due to some other problem?

[Peter87]

What is b initialized to?

[Akshit]

long a=2;
long long b=5;

[Peter87]

How much time it takes depend on many different things. Your machine, your compiler and how much time is spent in the checkprime function. Checking if a number is a prime could be a slow operation so it might very well take long time.

[Akshit]

It took more than 3 hours to complete half work.Thats too too much.

I have 2 gb ram and visual c++ 10.

Is there a way to reduce time?

[Peter87]

Try write a more efficient checkprime function.

Also make sure that you have turned on full compiler optimizations. It will probably not make much difference but it's easy to do.