补充课后作业

ch11/homework/kehou4.c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#define BUF_SIZE 30
+
+int main(int argc, char *argv[])
+{
+    int fds1[2], fds2[2];
+    //const char* 以"\0"作为结束符
+    char str1[] = "Do you like cooffee?";
+    char str2[] = "I like coffee";
+    char str3[] = "I like long legs";
+    char * str_arr[] = {str1, str2, str3};
+    char buf[BUF_SIZE];
+    pid_t pid;
+    int i;
+
+    pipe(fds1), pipe(fds2);
+    pid = fork();
+
+    if(pid == 0) 
+    {
+        for(i = 0; i < 3; ++i)
+        {
+            //strlen所作的是一个计数器的工作，它从内存的某个位置（可以是字符串开头，中间某个位置，甚至是某个不确定的内存区域）开始扫描，
+            //直到碰到第一个字符串结束符'\0'为止，然后返回计数器值(长度不包含'\0')
+            write(fds1[1], str_arr[i], strlen(str_arr[i]) + 1);//这里长度必须加上1，将字符串结束符加进去，否则会发生消息错乱
+            read(fds2[0], buf, BUF_SIZE);
+            printf("子进程收到的消息：%s\n", buf);
+        }
+    }
+    else
+    {
+        for(i = 0; i < 3; ++i)
+        {
+            read(fds1[0], buf, BUF_SIZE);
+            printf("父进程收到的消息：%s\n", buf);
+            write(fds2[1], str_arr[i], strlen(str_arr[i]) + 1);
+        }
+    }
+    return 0;
+}