コード:

bool checkCanPut(int _color, int _x, int _y) {
	return false;
}

コード:

	bool cantPut = false;//指定場所に置けないかどうかのフラグ変数。初期値は偽なので置ける(置けないcan'tPutが偽なので)

	while (1) {
		//～略～
		default:
			if (!checkCanPut(turn, cursorX, cursorY)) {	//指定場所にコマが置けなかったら
				cantPut = true;					//置けないフラグを真に
				break;
			}
			cells[cursorY][cursorX] = turn;
			turn ^= 1;
			break;
		}
		drawBoard();
		if (cantPut)						//置けないフラグが真だったら
			printf("Can't put!\n");
		else
			printf("%s turn.\n", colorNames[turn]);
	}

コード:

include<stdio.h>
#include<conio.h>
#include<stdlib.h>

#define BOARD_WIDTH 8
#define BOARD_HEIGHT 8
int cursorX=0, cursorY=0;

int turn;
int cells[BOARD_HEIGHT][BOARD_WIDTH] = {};
enum {
	COLOR_NONE=-1,
	COLOR_BLACK=0,
	COLOR_WHITE=1,
	COLOR_MAX
};
char colorNames[][5 + 1]{
	"Black",
	"White"
};

bool checkCanPut(int _color, int _x, int _y) {
	return false;
}

void drawBoard() {
	system("cls");
	for (int y = 0; y < BOARD_HEIGHT; y++) {
		for (int x = 0; x < BOARD_WIDTH; x++)
			if ((x == cursorX) && (y == cursorY))
				printf("◎");
			else {
				switch (cells[y][x]) {
				case COLOR_NONE:printf("・"); break;
				case COLOR_BLACK:printf("●"); break;
				case COLOR_WHITE:printf("〇"); break;
				}
			}
		printf("\n");
	}
}

int  main() {
	for (int y = 0; y < BOARD_HEIGHT; y++)
		for (int x = 0; x < BOARD_WIDTH; x++)
			cells[y][x] = COLOR_NONE;
	cells[3][3] = cells[4][4] = COLOR_WHITE;
	cells[4][3] = cells[3][4] = COLOR_BLACK;
	drawBoard();

	bool cantPut = false;

	while (1) {
		switch (_getch()) {
		case 'w':cursorY--; break;
		case 's':cursorY++; break;
		case 'a':cursorX--; break;
		case 'd':cursorX++; break;
		default:
			if (!checkCanPut(turn, cursorX, cursorY)) {
				cantPut = true;
				break;
			}
			cells[cursorY][cursorX] = turn;
			turn ^= 1;
			break;
		}
		drawBoard();
		if (cantPut)
			printf("Can't put!\n");
		else
			printf("%s turn.\n", colorNames[turn]);
	}
}