怎样使用GetAsyncKeyState()

#include <iostream>
#include <windows.h>
using namespace std;

/* Colors defined for SetColor(int) */
enum {
BLACK = 0,
DARK_BLUE = 1,
DARK_GREEN = 2,
TEAL = 3,
DARK_RED = 4,
DARK_PURPLE = 5,
GOLD = 6,
GREY = 7,
DARK_WHITE = 8,
BLUE = 9,
GREEN = 10,
CYAN = 11,
RED = 12,
PURPLE = 13,
YELLOW = 14,
WHITE = 15
};

void SetColor(const int foreground, const int background) {

int Color = foreground + (background * 16);
HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);
SetConsoleTextAttribute(hConsole, Color);

return;
}

void PlaceCursor(const int x, const int y) {

HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);

COORD PlaceCursorHere;
PlaceCursorHere.X = x;
PlaceCursorHere.Y = y;

SetConsoleCursorPosition(hConsole, PlaceCursorHere);
return;
}

int main() {

int UpArrow = 0;
int DownArrow = 0;
int LeftArrow = 0;
int RightArrow = 0;

PlaceCursor(15, 5);
cout << "UP, DOWN, LEFT, RIGHT";

PlaceCursor(15, 7);
SetColor(YELLOW, BLACK);
cout << "Last key(s) pressed: 0, 0, 0, 0";

while (true) {

/* Draw the box around: Last key(s) pressed */
PlaceCursor(14, 6);
SetColor(WHITE, BLACK);
cout << "ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»";
PlaceCursor(14, 7);
cout << "º";
PlaceCursor(46, 7);
cout << "º";
PlaceCursor(14, 8);
cout << "ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ";

UpArrow = GetAsyncKeyState(VK_UP);
DownArrow = GetAsyncKeyState(VK_DOWN);
LeftArrow = GetAsyncKeyState(VK_LEFT);
RightArrow = GetAsyncKeyState(VK_RIGHT);

//if (UpArrow == 0 || DownArrow != 0 || LeftArrow != 0 || RightArrow != 0) {
if (UpArrow == 0) {
PlaceCursor(0, 0);
SetColor(WHITE, BLACK);
cout << "UP ARROW    - ";

SetColor(RED, BLACK);
cout << "pressed/n";

PlaceCursor(36, 7);
SetColor(RED, BLACK);
cout << "0";
}
else {
PlaceCursor(0, 0);
SetColor(WHITE, BLACK);
cout << "UP ARROW    - ";

SetColor(GREEN, BLACK);
cout << "pressed/n";

PlaceCursor(36, 7);
SetColor(GREEN, BLACK);
cout << "1";
}

//if (DownArrow == 0 || UpArrow != 0 || LeftArrow != 0 || RightArrow != 0) {
if (DownArrow == 0) {
PlaceCursor(0, 1);
SetColor(WHITE, BLACK);
cout << "DOWN ARROW  - ";

SetColor(RED, BLACK);
cout << "pressed/n";

PlaceCursor(39, 7);
SetColor(RED, BLACK);
cout << "0";
}
else {
PlaceCursor(0, 1);
SetColor(WHITE, BLACK);
cout << "DOWN ARROW  - ";

SetColor(GREEN, BLACK);
cout << "pressed/n";

PlaceCursor(39, 7);
SetColor(GREEN, BLACK);
cout << "1";
}

//if (LeftArrow == 0 || UpArrow != 0 || DownArrow != 0 || RightArrow != 0) {
if (LeftArrow == 0) {
PlaceCursor(0, 2);
SetColor(WHITE, BLACK);
cout << "LEFT ARROW  - ";

SetColor(RED, BLACK);
cout << "pressed/n";

PlaceCursor(42, 7);
SetColor(RED, BLACK);
cout << "0";
}
else {
PlaceCursor(0, 2);
SetColor(WHITE, BLACK);
cout << "LEFT ARROW  - ";

SetColor(GREEN, BLACK);
cout << "pressed/n";

PlaceCursor(42, 7);
SetColor(GREEN, BLACK);
cout << "1";
}

//if (RightArrow == 0 || UpArrow != 0 || DownArrow != 0 || LeftArrow != 0) {
if (RightArrow == 0) {
PlaceCursor(0, 3);
SetColor(WHITE, BLACK);
cout << "RIGHT ARROW - ";

SetColor(RED, BLACK);
cout << "pressed/n";

PlaceCursor(45, 7);
SetColor(RED, BLACK);
cout << "0";
}
else {
PlaceCursor(0, 3);
SetColor(WHITE, BLACK);
cout << "RIGHT ARROW - ";

SetColor(GREEN, BLACK);
cout << "pressed/n";

PlaceCursor(45, 7);
SetColor(GREEN, BLACK);
cout << "1";
}

Sleep(50);
if (GetAsyncKeyState(VK_ESCAPE)) { exit(0); }
}

return 0;
}