在linux下用c编程软件下载

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>

#define SERVER "example.com"
#define PORT 80
#define FILENAME "downloaded_file.txt"

int main(int argc, char *argv[]) {
    int sock;
    struct sockaddr_in server;
    char request[256];
    char response[4096];
    FILE *file;

    // 创建套接字
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        perror("Socket creation error");
        return -1;
    }

    // 配置服务器地址
    server.sin_family = AF_INET;
    server.sin_port = htons(PORT);
    inet_pton(AF_INET, SERVER, &server.sin_addr);

    // 连接服务器
    if (connect(sock, (struct sockaddr *)&server, sizeof(server)) < 0) {
        perror("Connection failed");
        close(sock);
        return -1;
    }

    // 构造HTTP请求
    snprintf(request, sizeof(request), "GET /%s HTTP/1.1\r\nHost: %s\r\nConnection: close\r\n\r\n", FILENAME, SERVER);

    // 发送请求
    send(sock, request, strlen(request), 0);

    // 打开文件用于写入
    file = fopen(FILENAME, "wb");
    if (!file) {
        perror("File open error");
        close(sock);
        return -1;
    }

    // 接收响应并写入文件
    int total_bytes = 0;
    while (recv(sock, response, sizeof(response), 0) > 0) {
        fwrite(response, 1, strlen(response), file);
        total_bytes += strlen(response);
    }

    // 关闭文件和套接字
    fclose(file);
    close(sock);

    printf("Downloaded %d bytes\n", total_bytes);
    return 0;
}