DaniWeb Forum Index > Software Development > C++

Program that finds prime numbers

Please support our C++ advertiser: Intel Parallel Studio Home

•

Join Date: Oct 2007

Posts: 22

Reputation: people123 is an unknown quantity at this point

Solved Threads: 1

people123

Offline

Newbie Poster

Program that finds prime numbers

Oct 28th, 2007

So after a day or two of trying i finally found out how to do this, my question is, is there any way to do this that is more efficient without using the prime function?

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
using namespace std;
 
 
      int main()
{
 std::string line;
 
 int i, p, x;
 
 for(i = 3; i <=100; i++) {
 
       for(p=2; p<i; p++)
       {
                if((i%p) == 0) x = 0;
                }
                if(x != 0) cout << i << " is prime\n";
                x = 1;
                }
 
 
 
 
 getline(cin,line);
 cin.get();
 
 return 0;
}
#include <iostream>
using namespace std;


      int main()
{
 std::string line;
 
 int i, p, x;
 
 for(i = 3; i <=100; i++) {
       
       for(p=2; p<i; p++)
       {
                if((i%p) == 0) x = 0;
                }
                if(x != 0) cout << i << " is prime\n";
                x = 1;
                }
       
       
        
    
 getline(cin,line);
 cin.get();
 
 return 0;
}

•

Join Date: Aug 2005

Posts: 15,625

Reputation: Ancient Dragon has a reputation beyond repute

Solved Threads: 1496

Ancient Dragon Ancient Dragon is offline

Offline

Still Learning

Re: Program that finds prime numbers

Oct 28th, 2007

The formatting is terrible, maybe you have a mixture of tabs and spaces. I think you have a couple misplaced braces.

Last edited by Ancient Dragon; Oct 28th, 2007 at 8:48 pm.

Don't PM me with questions -- you might get a nasty PM in response. If you have a question then post it in one of the forums.

•

Join Date: Oct 2007

Posts: 22

Reputation: people123 is an unknown quantity at this point

Solved Threads: 1

people123

Offline

Newbie Poster

Re: Program that finds prime numbers

Oct 28th, 2007

how should i improve my formatting, can you please give me an example... i just get lost of what has to be where when im writing

•

Join Date: Aug 2005

Posts: 15,625

Reputation: Ancient Dragon has a reputation beyond repute

Solved Threads: 1496

Ancient Dragon Ancient Dragon is offline

Offline

Still Learning

Re: Program that finds prime numbers

Oct 28th, 2007

example. Note placement of braces and spacing. For more information read this by the author of the c++ language.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
using namespace std;
 
 
int main()
{
    std::string line;
 
    int i, p, x;
 
    for(i = 3; i <=100; i++) 
    {     
       for(p=2; p<i; p++)
       {
            if((i%p) == 0) 
                x = 0;
       }
       if(x != 0) 
             cout << i << " is prime\n";
       x = 1;
    }
    getline(cin,line);
    cin.get();
    return 0;
}
#include <iostream>
using namespace std;


int main()
{
    std::string line;
 
    int i, p, x;
 
    for(i = 3; i <=100; i++) 
    {     
       for(p=2; p<i; p++)
       {
            if((i%p) == 0) 
                x = 0;
       }
       if(x != 0) 
             cout << i << " is prime\n";
       x = 1;
    }
    getline(cin,line);
    cin.get();
    return 0;
}