Conway's game of life but it's ascii and on torus

#include <ncurses.h>
#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
#include <unistd.h>
#include <math.h>
#include <ctime>

int main()
{

    // Initialize ncurses
    setlocale(LC_ALL, "");
    initscr();
    cbreak();
    noecho();
    nodelay(stdscr, TRUE);

    float gps = 20; //generations per second

    uint sheight = 20;
    uint swidth = 30;

    //cell margin
    int mrg=1;
    int mrg2=mrg*2;

    int swm2 = swidth+mrg2;
    int shm2 = sheight+mrg2;

    // Declare the 2D array pointer
    bool** screen;
    bool** screenbuf;

    // Allocate the first dimension of the array
    screen = new bool*[swm2];
    screenbuf = new bool*[swm2];

    // Allocate the second dimension of the array for each row
    for (int i = 0; i < swm2; ++i) {
        screen[i] = new bool[shm2];
        screenbuf[i] = new bool[shm2];
    }

    int exit=0;

    //set zero
    for (int yi = 0; yi < shm2; yi += 1) {
        for (int xi = 0; xi < swm2; xi += 1) {
            screen   [xi][yi]=0;
            screenbuf[xi][yi]=0;
        }
    }

    //flyers and a rods
    for(int ofs=0;ofs<4;ofs++){
        int m=4*ofs;
        screen[(1+m)%swm2][(0+m)%shm2]=1;
        screen[(2+m)%swm2][(1+m)%shm2]=1;
        screen[(0+m)%swm2][(2+m)%shm2]=1;
        screen[(1+m)%swm2][(2+m)%shm2]=1;
        screen[(2+m)%swm2][(2+m)%shm2]=1;
        if(ofs%2==1){
            screen[(10+m)%swm2][(0+m)%shm2]=1;
            screen[(10+m)%swm2][(1+m)%shm2]=1;
            screen[(10+m)%swm2][(2+m)%shm2]=1;
        }
    }

    //preview
    clear();
    for (int yi = 0; yi < sheight; yi += 1) {
        for (int xi = 0; xi < swidth; xi += 1) {
            int xb = (xi + swm2 ) % swm2;
            int yb = (yi + shm2 ) % shm2;
            screen[xb][yb] ? printw("██") : printw("░░");
        }
        printw("\n");
    }
    refresh();

    getchar();

    clock_t stclock=0;
    clock_t ndclock,tdelta=0;
    uint long gen = 0;

    //generation loop
    do{
        clear();
        for (int yi = 0; yi < sheight; yi += 1) {
            for (int xi = 0; xi < swidth; xi += 1) {
                int xb = (xi + swm2 ) % swm2;
                int yb = (yi + shm2 ) % shm2;
                screen[xb][yb] ? printw("██") : printw("░░");
            }
            printw("\n");
        }
        printw("gen:%llu    gps:%f\n",gen,1000000.0/tdelta);

        clock();

        //copy to buffer
        for (int yi = 0; yi < shm2; yi += 1) {
            for (int xi = 0; xi < swm2; xi += 1) {
                screenbuf[xi][yi]=screen[xi][yi];
            }
        }

        //compute cell rules
        for (int yi = 0; yi < shm2; yi += 1) {
            for (int xi = 0; xi < swm2; xi += 1) {

                int xp = (xi + 1        ) % swm2;
                int xn = (xi - 1 + swm2 ) % swm2;
                int yp = (yi + 1        ) % shm2;
                int yn = (yi - 1 + shm2 ) % shm2;

                bool neig[8]={
                    screenbuf[xn][yp], //NE
                    screenbuf[xp][yi], //N
                    screenbuf[xp][yp], //NW
                    screenbuf[xn][yi], //W
                    screenbuf[xp][yn], //SW
                    screenbuf[xi][yp], //S
                    screenbuf[xn][yn], //SE
                    screenbuf[xi][yn]  //E
                };

                int neigsum=0;
                for(int i=0; i<sizeof(neig);i++){
                    neigsum+=neig[i];
                }

                if(neigsum==3){
                    screen[xi][yi]=1;
                }else if(neigsum==2){

                }else{
                    screen[xi][yi]=0;
                }

            }
        }
        gen++;

        //read key
        do{
            ndclock=clock();
            tdelta = ndclock-stclock;

            int keypress=getch();
            if (keypress != ERR) {
                switch (keypress) {
                    case 'q':   //quit
                        exit = 1;
                        break;
                    case '1':   //slow down
                        gps/=2;
                        break;
                    case '2':   //gps rst
                        gps=10;
                        break;
                    case '3':   //speed up
                        gps*=2;
                        break;
                }
            }
        }while(tdelta<1000000/gps);
        usleep(1000000/gps/2);
        stclock=clock();

    }while(!exit);

    endwin();

    //delete
    for (int i = 0; i < swm2; ++i) {
        delete[] screen[i];
    }
    delete[] screen;

    for (int i = 0; i < swm2; ++i) {
        delete[] screenbuf[i];
    }
    delete[] screenbuf;

    return 0;
}