实现了服务端和客户端计算器 P87

ch05/My_op_server.c

@@ -0,0 +1,107 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+
+#define BUF_SIZE 10240
+void error_handling(char *message);
+
+char res[10];
+char *calc(char *s)
+{
+    int len = strlen(s), i;
+    int n = 0;
+    for (i = 0; i < len; i++)
+        if (s[i] == ' ')
+        {
+            i++;
+            break;
+        }
+        else
+            n = n * 10 + (s[i] - '0');
+    int *num = malloc(sizeof(int) * n);
+    int tot = 0, x = 0;
+
+    for (; i < len; i++)
+    {
+        if (s[i] == '+' || s[i] == '*' || s[i] == '-')
+            break;
+        if (s[i] == ' ')
+        {
+            num[tot++] = x;
+            x = 0;
+        }
+        else
+            x = x * 10 + (s[i] - '0');
+    }
+    int ans = 0;
+    if (s[i] == '+')
+    {
+        for (int i = 0; i < tot; i++)
+            ans += num[i];
+    }
+    else if (s[i] == '*')
+    {
+        ans = 1;
+        for (int i = 0; i < tot; i++)
+            ans *= num[i];
+    }
+    else if (s[i] == '-')
+    {
+        ans = num[0];
+        for (int i = 1; i < tot; i++)
+            ans -= num[i];
+    }
+    free(num);
+    sprintf(res, "%d", ans);
+    return res;
+}
+int main(int argc, char *argv[])
+{
+    int serv_sock, clnt_sock;
+    char message[BUF_SIZE];
+    int str_len;
+
+    struct sockaddr_in serv_adr, clnt_adr;
+    socklen_t clnt_adr_sz;
+
+    if (argc != 2)
+    {
+        printf("Usage : %s <port>\n", argv[0]);
+        exit(1);
+    }
+
+    serv_sock = socket(PF_INET, SOCK_STREAM, 0);
+    if (serv_sock == -1)
+        error_handling("socket() error");
+
+    memset(&serv_adr, 0, sizeof(serv_adr));
+    serv_adr.sin_family = AF_INET;
+    serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
+    serv_adr.sin_port = htons(atoi(argv[1]));
+
+    if (bind(serv_sock, (struct sockaddr *)&serv_adr, sizeof(serv_adr)) == -1)
+        error_handling("bind() error");
+
+    if (listen(serv_sock, 5) == -1)
+        error_handling("listen() error");
+
+    clnt_adr_sz = sizeof(clnt_adr);
+    clnt_sock = accept(serv_sock, (struct sockaddr *)&clnt_adr, &clnt_adr_sz);
+    if (clnt_sock == -1)
+        error_handling("accept() error");
+    str_len = read(clnt_sock, message, BUF_SIZE);
+    write(clnt_sock, calc(message), str_len);
+    close(clnt_sock);
+    close(serv_sock);
+    return 0;
+}
+
+void error_handling(char *message)
+{
+    fputs(message, stderr);
+    fputc('\n', stderr);
+    exit(1);
+}