使用c代码，easyx库实现能够人机对决的五子棋。

非常感谢您的提问！以下是使用C代码和EasyX库实现人机对决的五子棋的示例代码：

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

#define BOARD_SIZE 15
#define CELL_SIZE 40
#define BOARD_LEFT 50
#define BOARD_TOP 50
#define BOARD_RIGHT (BOARD_LEFT + BOARD_SIZE * CELL_SIZE)
#define BOARD_BOTTOM (BOARD_TOP + BOARD_SIZE * CELL_SIZE)
#define PLAYER 1
#define COMPUTER 2

int board[BOARD_SIZE][BOARD_SIZE] = {0};
int playerColor = RED;
int computerColor = YELLOW;

void drawBoard()
{
    setbkcolor(WHITE);
    cleardevice();
    setlinestyle(PS_SOLID, 2);
    setlinecolor(BLACK);
    for (int i = 0; i <= BOARD_SIZE; i++)
    {
        line(BOARD_LEFT, BOARD_TOP + i * CELL_SIZE, BOARD_RIGHT, BOARD_TOP + i * CELL_SIZE);
        line(BOARD_LEFT + i * CELL_SIZE, BOARD_TOP, BOARD_LEFT + i * CELL_SIZE, BOARD_BOTTOM);
    }
    setfillcolor(BLACK);
    solidcircle(BOARD_LEFT + 3 * CELL_SIZE, BOARD_TOP + 3 * CELL_SIZE, 5);
    solidcircle(BOARD_LEFT + 11 * CELL_SIZE, BOARD_TOP + 3 * CELL_SIZE, 5);
    solidcircle(BOARD_LEFT + 7 * CELL_SIZE, BOARD_TOP + 7 * CELL_SIZE, 5);
    solidcircle(BOARD_LEFT + 3 * CELL_SIZE, BOARD_TOP + 11 * CELL_SIZE, 5);
    solidcircle(BOARD_LEFT + 11 * CELL_SIZE, BOARD_TOP + 11 * CELL_SIZE, 5);
}

void putChess(int x, int y, int color)
{
    setfillcolor(color);
    solidcircle(BOARD_LEFT + x * CELL_SIZE, BOARD_TOP + y * CELL_SIZE, CELL_SIZE / 2 - 2);
}

int checkWin(int x, int y, int color)
{
    int count = 1;
    for (int i = x - 1; i >= 0 && board[i][y] == color; i--)
        count++;
    for (int i = x + 1; i < BOARD_SIZE && board[i][y] == color; i++)
        count++;
    if (count >= 5)
        return color;

    count = 1;
    for (int i = y - 1; i >= 0 && board[x][i] == color; i--)
        count++;
    for (int i = y + 1; i < BOARD_SIZE && board[x][i] == color; i++)
        count++;
    if (count >= 5)
        return color;

    count = 1;
    for (int i = x - 1, j = y - 1; i >= 0 && j >= 0 && board[i][j] == color; i--, j--)
        count++;
    for (int i = x + 1, j = y + 1; i < BOARD_SIZE && j < BOARD_SIZE && board[i][j] == color; i++, j++)
        count++;
    if (count >= 5)
        return color;

    count = 1;
    for (int i = x - 1, j = y + 1; i >= 0 && j < BOARD_SIZE && board[i][j] == color; i--, j++)
        count++;
    for (int i = x + 1, j = y - 1; i < BOARD_SIZE && j >= 0 && board[i][j] == color; i++, j--)
        count++;
    if (count >= 5)
        return color;

    return 0;
}

int evaluate(int color)
{
    int score = 0;
    for (int i = 0; i < BOARD_SIZE; i++)
    {
        for (int j = 0; j < BOARD_SIZE; j++)
        {
            if (board[i][j] == color)
            {
                int count = 1;
                for (int k = i - 1; k >= 0 && board[k][j] == color; k--)
                    count++;
                for (int k = i + 1; k < BOARD_SIZE && board[k][j] == color; k++)
                    count++;
                if (count >= 5)
                    return 1000000;

                count = 1;
                for (int k = j - 1; k >= 0 && board[i][k] == color; k--)
                    count++;
                for (int k = j + 1; k < BOARD_SIZE && board[i][k] == color; k++)
                    count++;
                if (count >= 5)
                    return 1000000;

                count = 1;
                for (int k = i - 1, l = j - 1; k >= 0 && l >= 0 && board[k][l] == color; k--, l--)
                    count++;
                for (int k = i + 1, l = j + 1; k < BOARD_SIZE && l < BOARD_SIZE && board[k][l] == color; k++, l++)
                    count++;
                if (count >= 5)
                    return 1000000;

                count = 1;
                for (int k = i - 1, l = j + 1; k >= 0 && l < BOARD_SIZE && board[k][l] == color; k--, l++)
                    count++;
                for (int k = i + 1, l = j - 1; k < BOARD_SIZE && l >= 0 && board[k][l] == color; k++, l--)
                    count++;
                if (count >= 5)
                    return 1000000;

                score += count * count;
            }
        }
    }
    return score;
}

int computerMove()
{
    int maxScore = -1;
    int bestX = -1, bestY = -1;
    for (int i = 0; i < BOARD_SIZE; i++)
    {
        for (int j = 0; j < BOARD_SIZE; j++)
        {
            if (board[i][j] == 0)
            {
                board[i][j] = computerColor;
                int score = evaluate(computerColor) + evaluate(playerColor);
                board[i][j] = 0;
                if (score > maxScore)
                {
                    maxScore = score;
                    bestX = i;
                    bestY = j;
                }
            }
        }
    }
    return bestX * BOARD_SIZE + bestY;
}

int main()
{
    initgraph(BOARD_RIGHT + 50, BOARD_BOTTOM + 50);
    drawBoard();
    int turn = PLAYER;
    while (1)
    {
        if (turn == PLAYER)
        {
            int x, y;
            while (1)
            {
                if (_kbhit())
                {
                    char ch = _getch();
                    if (ch == 27) // ESC
                        exit(0);
                    else if (ch == ' ') // SPACE
                    {
                        x = (getmousex() - BOARD_LEFT) / CELL_SIZE;
                        y = (getmousey() - BOARD_TOP) / CELL_SIZE;
                        if (x >= 0 && x < BOARD_SIZE && y >= 0 && y < BOARD_SIZE && board[x][y] == 0)
                            break;
                    }
                }
            }
            putChess(x, y, playerColor);
            board[x][y] = PLAYER;
            int winner = checkWin(x, y, PLAYER);
            if (winner)
            {
                if (winner == PLAYER)
                    outtextxy(BOARD_RIGHT + 10, BOARD_TOP + 100, "You win!");
                else
                    outtextxy(BOARD_RIGHT + 10, BOARD_TOP + 100, "Computer wins!");
                break;
            }
            turn = COMPUTER;
        }
        else
        {
            int move = computerMove();
            int x = move / BOARD_SIZE;
            int y = move % BOARD_SIZE;
            putChess(x, y, computerColor);
            board[x][y] = COMPUTER;
            int winner = checkWin(x, y, COMPUTER);
            if (winner)
            {
                if (winner == PLAYER)
                    outtextxy(BOARD_RIGHT + 10, BOARD_TOP + 100, "You win!");
                else
                    outtextxy(BOARD_RIGHT + 10, BOARD_TOP + 100, "Computer wins!");
                break;
            }
            turn = PLAYER;
        }
    }
    while (!_kbhit())
        Sleep(100);
    closegraph();
    return 0;
}

希望这个示例代码能够帮助您实现人机对决的五子棋！