Linux程序设计考试例题

例题1程序A生成1个文件，其大小为1000字节，其内容为小写字母abcd...z的循环。试编写该程序。文件名#include<>#include<>#include<>intmain(){charx;inti;intfd=open("aa",O_CREAT|O_TRUNC|O_WRONLY,0666);if(fd<0){printf("openfileerror!\r\n");exit(0);};for(i=0;i<1000;i++){x='a'+(i%26);write(fd,&x,1);}close(fd);}例题2读出一个文件的倒数第2个字节和倒数第1个字节，显示在屏幕上。并且显示出当前时间。文件名#include<>#include<>#include<>#include<>intmain(){charx[2];intfd=open("",O_RDONLY);if(fd<0){printf("openfileerror!\r\n");exit(0);};lseek(fd,-3,SEEK_END);read(fd,x,2);printf("倒数第二和第一字节为％c%c\r\n",x[0Lx[1]);close(fd);time_tt;time(&t);printf("当前时间:%s",asctime(localtime(&t)));}例题3产生一个进程树父进程有3个子进程，这三个子进程分别有2个子进程。每个进程退出前打印自己的进程id号文件名#include<>#include<>#include<>intmain(){intret,i;for(i=0;i<3;i++){ret=fork();if(ret==0)break;}if(ret==0)for(i=0;i<2;i++){ret=fork();if(ret==0)break;}sleep(10);printf("thread%disexitingnow\r\n",getpid());}测试方法：在另一窗口#su#pstree-a例题4编写两程序实现消息队列通信程序名#include<>#include<>#include<>#include<>#include<sys/>#include<sys/>#include<sys/>#include<sys/>structmsgbuf{longmtype;charctext[100];};intmain(){structmsgbufbuf;intmsid;msid=msgget(0x1000,0666|IPC_CREAT);if(msid<0){printf("openfailed\r\n");exit(0);};while(1){=getpid();scanf("%s",;while((msgsnd(msid,&buf,strlen,0))<0){if(errno==EINTR)continue;return;}if(strcmp,"exit")==0)break;}return0;}文件名#include<>#include<>#include<>#include<>#include<sys/>#include<sys/>#include<sys/>#include<sys/>structmsgbuf{longmtype;charctext[100];};intmain(){structmsgbufbuf;intmsid,ret;msid=msgget(0x1000,0666|IPC_CREAT);if(msid<0){printf("openfailed\r\n");exit(0);};while(1){memset(&buf,0,sizeof(buf));while((ret=msgrcv(msid,&buf,sizeof,0,0))<0){if(errno==EINTR)continue;return;}printf("%d%s\r\n",,;if(strcmp,"exit")==0)break;}msgctl(msid,IPC_RMID,NULL);return0;}测试方法首先运行t4snd,输入三行字符串，最后一行必须是小写字母的exit#./t4sndHelloWorldexit则t4snd自动退出然后运行t4rev#./t4rev例题5网络TCP的服务端文件名#include<>#include<>#include<>#include<arpa/>#include<sys/>#include<sys/>#include<>#definePORT82#defineBUFSIZE512charbuf[BUFSIZE+1];intmain(){mv如果这时候报错并且不是代码问题和的问题，则可能是xwindow的问题，应该按照下面的方式解决问题：#exit$xhost+$./mv注意你