3.4完成

ch03/inet_ntoa.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <string.h>
+#include <arpa/inet.h>
+
+int main(int argc, char *argv[])
+{
+    struct sockaddr_in addr1, addr2;
+    char *str_ptr;
+    char str_arr[20];
+
+    addr1.sin_addr.s_addr = htonl(0x1020304);
+    addr2.sin_addr.s_addr = htonl(0x1010101);
+    //把addr1中的结构体信息转换为字符串的IP地址形式
+    str_ptr = inet_ntoa(addr1.sin_addr);
+    strcpy(str_arr, str_ptr);
+    printf("Dotted-Decimal notation1: %s \n", str_ptr);
+
+    inet_ntoa(addr2.sin_addr);
+    printf("Dotted-Decimal notation2: %s \n", str_ptr);
+    printf("Dotted-Decimal notation3: %s \n", str_arr);
+    return 0;
+}