Question

I’ve to write a program that prints prime numbers from 1 to 100 (every 5 numbers on a line) using 2 functions: the first to test the number if it’s odd and the second to test it if it’s prime

I wrote that code but it didn’t work
it only prints the last prime number before 100

thanx ^_^

#include "stdafx.h"

bool is_odd(int x)
{
    if (x%2==0)
        return false;
    else
        return true;
}

bool is_prime(int x)
{
    int j=0;
    if (!(is_odd(x)))
        return false;

    if(is_odd(x))
    {
        for(int i=1;i<=x;i++)
            if (x%i==0)
                j=j+1;

        if (j==2)
            return true;
        else
            return false;
    }
}


void main()
{
    int x[100][100];
    int i=1;    

    while (i<=100) 
    {
        for(int j=1;j<=20;j++)
            for(int k=1;k<=5;k++)
                if (is_prime(i))
                    x[j][k]=i;
        i++;
    }
    for(int j=1;j<=20;j++)
    {
        for(int k=1;k<=5;k++)
            cout<<x[j][k]<<' ';
        cout<<endl;
    }
}

Answer 1

Such amazing complexity for a simple problem. You don’t need arrays to do this, not even multi-dimensional arrays.

int main()
{
    int count = 0;
    for (int i = 1; i <= 100; ++i)
    {
        if (is_prime(i))
        {
            cout << i << ' ';
            ++count;
            if (count == 5)
            {
                cout << endl;
                count = 0;
            }
        }
    }
    cout << endl;
}