Programming Forums - prime numbers now with arrays

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prime numbers now with arrays

so this really got me i, i have to write the numbers to an array then to the file, all i keep getting is numbers 0-99 however in the file help would be greatly appreciated. :?:

#include <iostream>
#include <fstream>
using namespace std;
 
bool isPrime(int c);
void write_array(int x, ofsteam &outfile);
void write_prime(int num, int p);
 
int main()
{
        int p = 0;
        int count;
        const int arrays = 100
        ofstream pfile("Prime.txt"); //Declare variables
 
        for (int c =0; c<100,c++) //Write all the arrays to 0
                arrays[c]=0;
 
 
        for (int x = 2; x < 100; x++) //Finding The Prime Numbers
        {
                if(isPrime(x))
                {
                        write_array(x, pos); //Writing Primes to Array
                        pos++
                }
 
        }
 
 
        for(count = 0; arrays[count] != 0; count ++)                //Write arrays to file
                write_prime(arrays[count],pfile);
 
        pfile.close();
        return 0;
}
 
bool isPrime(int c)
{
        for (int y = 2; y < c; y++)
        {        
                if(c % y == 0)
                {
                        return  false;
                        break;
                }
 
        }
        return  true;
}
 
void write_prime(int p, ofstream &pfile)
{
        pfile << p << endl;
 
}
 
void write_array(int num, int p)
{
        arrays[p]=num;
 
        return;
}

Re: prime numbers now with arrays

Quote:

Originally Posted by gmann145 (Post 141230)

so this really got me i, i have to write the numbers to an array then to the file, all i keep getting is numbers 0-99 however in the file help would be greatly appreciated. :?:

#include <iostream>
#include <fstream>
using namespace std;
 
bool isPrime(int c);
void write_array(int x, ofsteam &outfile);
void write_prime(int num, int p);
 
int main()
{
        int p = 0;
        int count;
        const int arrays = 100
        ofstream pfile("Prime.txt"); //Declare variables
 
        for (int c =0; c<100,c++) //Write all the arrays to 0
                arrays[c]=0;
 
 
        for (int x = 2; x < 100; x++) //Finding The Prime Numbers
        {
                if(isPrime(x))
                {
                        write_array(x, pos); //Writing Primes to Array
                        pos++
                }
 
        }
 
 
        for(count = 0; arrays[count] != 0; count ++)                //Write arrays to file
                write_prime(arrays[count],pfile);
 
        pfile.close();
        return 0;
}
 
bool isPrime(int c)
{
        for (int y = 2; y < c; y++)
        {        
                if(c % y == 0)
                {
                        return  false;
                        break;
                }
 
        }
        return  true;
}
 
void write_prime(int p, ofstream &pfile)
{
        pfile << p << endl;
 
}
 
void write_array(int num, int p)
{
        arrays[p]=num;
 
        return;
}

Wow, where to start? arrays is a const int (with no semicolon), but later you try to use it as an array. Also your for loop has a comma instead of a semicolon. p is apparently trying to be pos. Your functions are too simple to be functions (you make it more confusing than helpful).

        for (int c =0; c<100;c++) //Write all the arrays to 0

                arrays[c]=0;

This can be eliminated by just using pos as a limit in the last for loop.

I think you should go over a tutorial from the beginning and rethink your logic here, everything is more complicated than it needs to be.

Re: prime numbers now with arrays

I'm surprised you got any output since your code does not compile. You should make sure your program works using standard output first.