下面是一個簡單的C++服務器端程序，利用recv函數接收數據：

#include <iostream>
#include <cstring>
#include <sys/socket.h>
#include <netinet/in.h>

int main() {
    // 創建socket
    int server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd == -1) {
        std::cerr << "Error creating socket" << std::endl;
        return 1;
    }

    // 綁定端口
    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = INADDR_ANY;
    server_addr.sin_port = htons(8888);

    if (bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        std::cerr << "Bind failed" << std::endl;
        return 1;
    }

    // 監聽端口
    listen(server_fd, 3);

    // 接受連接
    int client_fd;
    struct sockaddr_in client_addr;
    int addr_len = sizeof(client_addr);
    client_fd = accept(server_fd, (struct sockaddr *)&client_addr, (socklen_t *)&addr_len);

    // 接收數據
    char buffer[1024] = {0};
    int valread = recv(client_fd, buffer, 1024, 0);
    
    std::cout << "Received: " << buffer << std::endl;

    return 0;
}

這個程序創建一個服務器端socket，綁定端口，監聽端口，并接受連接。接受到連接后，利用recv函數從客戶端接收數據，并輸出到控制臺。