补充课后作业

ch18/homework/echo_client.c

@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+
+#define BUF_SIZE 1024
+void error_handling(char* message);
+
+int main(int argc, char* argv[])
+{
+    int sock;
+    char message[BUF_SIZE];
+    int str_len;
+    struct sockaddr_in serv_adr;
+
+    if(argc != 3) {
+        printf("Usage : %s <IP> <port>\n", argv[0]);
+        exit(1);
+    }
+    /*创建tcp套接字*/
+    sock = socket(PF_INET, SOCK_STREAM, 0);
+    if(sock == -1)
+        error_handling("socket() error");
+    /*初始化*/
+    memset(&serv_adr, 0, sizeof(serv_adr));
+    serv_adr.sin_family = AF_INET;
+    serv_adr.sin_addr.s_addr = inet_addr(argv[1]);//string转大端序整型
+    serv_adr.sin_port = htons(atoi(argv[2]));
+    /*建立连接*/
+    if(connect(sock, (struct sockaddr*)&serv_adr, sizeof(serv_adr)) == -1)
+        error_handling("connect() error");
+    else
+        puts("Connected...........");
+
+    while(1)
+    {
+        fputs("Input message(Q to quit): ", stdout);
+        fgets(message, BUF_SIZE, stdin);
+        //实现按q或者Q退出
+        if(!strcmp(message, "q\n") || !strcmp(message, "Q\n"))
+            break;
+        
+        write(sock, message, strlen(message));
+        str_len = read(sock, message, BUF_SIZE - 1);
+        message[str_len] = 0;
+        printf("Message from server: %s", message);
+    }
+    close(sock);
+    return 0;
+}
+
+void error_handling(char* message)
+{
+    fputs(message, stderr);
+    fputc('\n',stderr);
+    exit(1);
+}