/media/sda-magnetic/david/Dokumente-15/fernuni-hagen/cs-i-ii/fsm/fsm/2021-04-21quine-state-.../prim3.c

#include <stdio.h>

int is_prim (int x) {
    int i;
    
    if (x == 2)
        return 1;
    
    if ((x % 2) == 0)
        return 0;
    
    for (i = 3;  i < x;  i += 2) 
        if ((x % i) == 0)
            return 0;
return 1;
}

int main (void) {
    int i;
    int x;
    
    int a [4069];
    int n;
    
    x = 6;
    
    for (x = 1, n = 0;  x < 20;  x++) {
        if (is_prim (x) == 0)
            printf ("%i ist keine Primzahl\n", x);
        else {   
            printf ("%i ist eine Primzahl\n", x);
            a [n++] = x;
        }
    }
    
    for (i = 1;  i < n;  i++)
        printf ("%i\n", a [i]);
    
return 0;
}