Mini-Twos

#include<iostream>
#include<ctime>
#include<cstdlib>
#include<array>
#include<iomanip>
#include<conio.h>
using namespace std;
array<int,16> b,c;
int r(){return rand()%3;}
void main(){
    srand(time(NULL));
    int ch = 0;
    int dx=0,dy=0;
    b[9] = 1; b[10] = 2;
    do {
        system("cls");
        if (ch==72) dy=1; if (ch==80) dy=-1;
        if (ch==75) dx=-1; if (ch==77) dx=1;
        bool g = dx!=0 || dy!=0;
        bool m = !g || (ch==0);
        while(g){
            g = false;
            int d = (dx==1 || dy==-1);
            for(int i=0;i<16;i++){
                int ii = (dx==-1 || dy==-1)?15-i:i;
                int j=ii/4;
                int ni = (dx==1)?(ii+1):((dx==-1)?(ii-1):((dy==1)?(ii-4):(ii+4)));
                bool go = b[ii] && ((dx==1 && ii%4!=3) || (dx==-1 && ii%4!=0) || (dy==1 && j%4!=0) || (dy==-1 && j%4!=3));
                if (go){
                    if (b[ii]==b[ni]){
                        b[ii]=0;
                        b[ni]*=2;
                        g = true;
                        m = true;
                    }
                    else if (b[ni]==0){
                        b[ni] = b[ii];
                        b[ii] = 0;
                        g = true;
                        m = true;
                    }
                }
            }
        }
        for(int i=0;i<16;i++){
            int j=i/4;
            bool go = (b[i]==0) && ((dx==1 && i%4==0) || (dx==-1 && i%4==3) || (dy==1 && j%4==3) || (dy==-1 && j%4==0));
            if (go) b[i] = r();
        }
        for(int i=0;i<16;i++){
            cout << setw(3) << setfill(' ') << b[i] << ' ' << (i%4==3?"\n":"");
        }
        cout << "\n";

        if (!m){
            int score = 0;
            for(auto i: b) score+=i;
            cout << "Score: " << score;
            return;
        }
        dx = dy = 0;
    }
    while((ch = _getch()) != 27);
}