Linuxc 进程间通信之匿名管道2 兄弟间通信

利用匿名管道实现兄弟进程间通信，要求
1.兄进程发送字符串“This is elder brother ，pid is (兄进程进程号)”给弟进程；
2.弟进程收到兄进程发送的数据后，给兄进程回复“This is younger brother ，pid is(第进程进程号)”；

源代码：

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc,char *argv[])
{
  char str1[50],num1[50],str2[50],num2[50];
        int fd1[2],fd2[2];//0用于读，1用于写
        pipe(fd1);
     pipe(fd2);
        int pid=fork();
        if(pid==0)
        {
  close(fd1[0]);
  close(fd2[1]);
                //char str[50],num[10];
  strcpy(str1,"This is elder brother,pid is ");
  sprintf(num1,"%d",getpid());
  strcat(str1,num1);
  write(fd1[1],str1,50);
                read(fd2[0],str2,50);  
   printf("\n%s\n",str2);
        }
        else if(pid>0)
        {
  int n=fork();
  if(n==0)
  {
   close(fd1[1]);
                 close(fd2[0]);
                 //char str[50],num[10];
                 read(fd1[0],str1,50);
                 printf("\n%s\n",str1);
   strcpy(str2,"This is younger brother,pid is ");
   sprintf(num2,"%d",getpid());
                 strcat(str2,num2);
   write(fd2[1],str2,50);
   
  }
  else if (n>0)
  {
   close(fd1[0]);
                 close(fd2[1]);
   close(fd2[0]);
                 close(fd1[1]);

  }
         }
 else
 {
  perror("fork error;");
 }      
        return 0;
} 

匿名管道相关函数请参考：点击打开链接
https://blog.csdn.net/qq_37192076/article/details/80456769