Windows Socket API 实现一个以下功能：客户端实现连接服务端，发送一串字符串后服务端会回一个字符串客户端再进行接收。

要使用Windows Socket API（Winsock）实现客户端和服务端之间的通信，你可以按照以下步骤操作：

**服务端（Server.py）**:

import socket

# 创建socket对象
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# 设置服务器地址和端口
host = "localhost"
port = 12345

# 绑定地址并监听
server_socket.bind((host, port))
server_socket.listen(1)

while True:
    # 接受客户端连接
    client_socket, addr = server_socket.accept()
    
    try:
        # 接收客户端消息
        received_data = client_socket.recv(1024)
        
        # 回复消息
        response = "Received: " + received_data.decode()
        client_socket.sendall(response.encode())
        
        # 关闭客户端连接
        client_socket.close()
    except Exception as e:
        print(f"Error: {e}")

**客户端（Client.py）**:

import socket

# 创建socket对象
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# 设置服务器地址和端口
host = "localhost"
port = 12345

try:
    # 连接到服务器
    client_socket.connect((host, port))

    # 发送字符串
    message = "Hello from Client!"
    client_socket.sendall(message.encode())

    # 接收服务端响应
    received_data = client_socket.recv(1024).decode()
    print(f"Received from Server: {received_data}")

finally:
    # 关闭连接
    client_socket.close()

要在命令行运行这两个程序，首先启动服务端`Server.py`，然后启动客户端`Client.py`。客户端会向服务端发送字符串，服务端接收到后返回一个包含接收到的消息的回复。