我想通过wasd移动小球，编译能成功但getchar无法使用

#include<iostream>
#include<conio.h>
#include<easyx.h>
#include<windows.h>
int main() {
	int x;
	int y;
	char a;
	x = 60;
	y = 540;

	initgraph(800, 600);
	setbkcolor(WHITE);
	cleardevice();
	setlinecolor(BLACK);
	setfillcolor(YELLOW);
	fillcircle(x, y, 50);
	for (;;) {
		a = getchar();
		if (a == 'd') {
			x++;
		}
		if (a == 'a') {
			x--;
		}
		if (a == 'w') {
			y--;
		}
		if (a == 's') {
			y++;
		}
		cleardevice();
		fillcircle(x, y, 50);
	}
}