#include <iostream>
#include <time.h>
using namespace std;
int* add_end(int *ar, int &n, int num);
int* func3(int *ar, int &n);
int* func2(int *ar, int &n);
int* func1(int *ar, int &n);
void set(int *ar, int n);
void print(int *ar, int n);
void main() {
    setlocale(LC_ALL, "ru");
    srand(time(0));
    int n;
    cout << "Введiть розмiр масиву: ";
    cin >> n;
    int* ar = new int[n];
    set(ar, n);
    print(ar, n);
    int*(*p[3])(int*, int&) = { func1,func2,func3 };
    int choice;
    cout << "1 - залишити простi числа з масиву \n2 - залишити числа кратнi 3 з масиву \n3 - залишити парнi числа з масиву \nВведiть вибiр:";
    cin >> choice;
    *ar = *p[choice - 1](ar, n);
    print(ar, n);
    system("pause");
}
int* add_end(int *ar, int &n, int num) {
    int* p = new int[n + 1];
    for (int i = 0; i < n; i++) {
        p[i] = ar[i];
    }
    p[n] = num;
    delete[]ar;
    n++;
    return p;
}
int* func3(int *ar, int &n) {
    int nn = n;
    n = 0;
    int* p = new int[n];
    int num = 0;
        for (int i = 0; i < nn; i++) {
            num = ar[i];
            ar[i] % 2 == 0 ? (p = add_end(p, n, num)) || (i += 0) : (i += 0);
        } 
    delete[]ar;
    return p;
}
int* func2(int *ar, int &n) {
    int nn = n;
    n = 0;
    int* p = new int[n];
    int num = 0;
    for (int i = 0; i < nn; i++) {
        num = ar[i];
        ar[i] % 3 == 0 ? (p = add_end(p, n, num)) || (i += 0) : (i += 0);
    }
    delete[]ar;
    return p;
}
int* func1(int *ar, int &n) {
    int nn = n;
    n = 0;
    int* p = new int[n];
    int b = 0;
    int num = 0;
    for (int i = 0; i < nn; i++) {
        b = 0;
        for (int c = 1; c < ar[i]; c++) {
            ar[i] % c == 0 ? (ar[i] >= 0 ? (b++) : (b += 0)) : b += 0;
        }
        num = ar[i];
        b < 3 ? (p = add_end(p, n, num)) || (b += 0) : (b += 0);
    }
    delete[]ar;
    return p;
}
void set(int *ar, int n) {
    for (int i = 0; i < n; i++) {
        *(ar + i) = rand() % 101 - 50;
    }
}
void print(int *ar, int n) {
    for (int i = 0; i < n; i++) {
        cout << *(ar + i) << " ";
    }
    cout << "\n";
}