include <myhead.h>
oid *task( void *file_size)int file_size1=*(int*)file_size;//打開源文件int fd=open("./hello",O_RDONLY);if(fd==-1){perror("open error\n");return NULL;}//打開目標文件int fd1=open("./world",O_WRONLY);if(fd1==-1){perror("open error\n");                                                                                                                                                       return NULL;}int num=file_size1/2;//移動光標lseek(fd,num,SEEK_SET);lseek(fd,num,SEEK_SET);char arr1[50]="";while(1){int size=read(fd,arr1,sizeof(arr1));if(size==0){break;}write(fd1,arr1,size);}nt main(int argc, const char *argv[])if(argc!=3){printf("格式錯誤：%s <源文件> <目標文件> ",argv[0]);return -1;}//打開源文件int fd=open(argv[1],O_RDONLY);if(fd==-1){perror("open error\n");return -1;}//計算文件大小int file_size=lseek(fd,0,SEEK_END);//計算拷貝的大小int helf_size=file_size/2;//創建目標文件int fd1=open(argv[2],O_WRONLY|O_CREAT|O_TRUNC,0664);if(fd1==-1){perror("open and creat file error\n");return -1;}//創建一個線程//定義一個線程變量，用來接收線程號pthread_t tid=-1;if(pthread_create(&tid,NULL,task,&file_size)!=0){printf("pthread create error\n");return -1;}//拷貝前一半內容//把光標移到文件開頭lseek(fd,0,SEEK_SET);lseek(fd1,0,SEEK_SET);char arr[50]="";int temp;int size;while(1){size=read(fd,arr,sizeof(arr));temp+=size;if(size==0&&temp>helf_size){write(fd1,arr,size-(temp-helf_size));break;}write(fd1,arr,size);}return 0;