使用客户端服务器模型反转C / C++中的字符串

本文介绍了客户端和服务器的设置，其中客户端连接，将字符串发送到服务器，并且服务器显示原始字符串，并使用套接字连接将反向字符串发送到客户端。

先决条件：套接字编程

例子：

Input : welcome
Output :emoclew

Input :geeks for geeks
Output :skeeg rof skeeg

解释
在这种情况下，首先建立客户端-服务器连接。建立连接后，客户端将通过发送系统调用将用户输入的字符串发送到服务器。在服务器端，服务器将等待客户端发送的字符串。服务器通过读取系统调用读取字符串。此后，服务器将反转字符串并将其发送回客户端。

编译：
1.首先以以下方式运行服务器程序

gcc Server.c -o server

2.在另一个终端上运行客户端程序

gcc Client.c -o client

3.服务器程序正在等待客户端发送的字符串。
4.在客户端输入字符串。
5.服务器程序将打印原始字符串。
6.客户端程序将打印反向字符串。

客户端

C

// C client code to send string to reverse
#include 
#include 
#include 
#include 
#include 
#include 
#include 
  
#define PORT 8090
  
// Driver code
int main()
{
    struct sockaddr_in address;
    int sock = 0, valread;
    struct sockaddr_in serv_addr;
    char str[100];
  
    printf("\nInput the string:");
    scanf("%[^\n]s", str);
  
    char buffer[1024] = { 0 };
  
    // Creating socket file descriptor
    if ((sock = socket(AF_INET,
                       SOCK_STREAM, 0))
        < 0) {
        printf("\n Socket creation error \n");
        return -1;
    }
  
    memset(&serv_addr, '0', sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(PORT);
  
    // Convert IPv4 and IPv6 addresses from
    // text to binary form 127.0.0.1 is local
    // host IP address, this address should be
    // your system local host IP address
    if (inet_pton(AF_INET, "127.0.0.1",
                  &serv_addr.sin_addr)
        <= 0) {
        printf("\nAddress not supported \n");
        return -1;
    }
  
    // connect the socket
    if (connect(sock, (struct sockaddr*)&serv_addr,
                sizeof(serv_addr))
        < 0) {
        printf("\nConnection Failed \n");
        return -1;
    }
  
    int l = strlen(str);
  
    // send string to server side
    send(sock, str, sizeof(str), 0);
  
    // read string sent by server
    valread = read(sock, str, l);
  
    printf("%s\n", str);
  
    return 0;
}

服务器

C

// Server C code to reverse a
// string by sent from client
#include 
#include 
#include 
#include 
#include 
#include 
  
#define PORT 8090
  
// Driver code
int main()
{
    int server_fd, new_socket, valread;
    struct sockaddr_in address;
    char str[100];
    int addrlen = sizeof(address);
    char buffer[1024] = { 0 };
    char* hello = "Hello from server";
  
    // Creating socket file descriptor
    if ((server_fd = socket(AF_INET, 
                          SOCK_STREAM, 0)) == 0) {
        perror("socket failed");
        exit(EXIT_FAILURE);
    }
  
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);
  
    // Forcefully attaching socket to
    // the port 8090
    if (bind(server_fd, (struct sockaddr*)&address, 
                          sizeof(address)) < 0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }
  
    // puts the server socket in passive mode
    if (listen(server_fd, 3) < 0) {
        perror("listen");
        exit(EXIT_FAILURE);
    }
    if ((new_socket = accept(server_fd,
                  (struct sockaddr*)&address,
                  (socklen_t*)&addrlen)) < 0) {
        perror("accept");
        exit(EXIT_FAILURE);
    }
  
    // read string send by client
    valread = read(new_socket, str,
                   sizeof(str));
    int i, j, temp;
    int l = strlen(str);
  
    printf("\nString sent by client:%s\n", str);
  
    // loop to reverse the string
    for (i = 0, j = l - 1; i < j; i++, j--) {
        temp = str[i];
        str[i] = str[j];
        str[j] = temp;
    }
  
    // send reversed string to client
    // by send system call
    send(new_socket, str, sizeof(str), 0);
    printf("\nModified string sent to client\n");
  
    return 0;
}

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