线程练习题

#include 
#include 
#include 
#include 
char buf[]="1234567";
 
void* func(void* arg){
    int len,i=0;
    char temp;
    while(1){
        len=strlen(buf)-1;
        i=0;
        while(buf[i]!='\0'&&i2){
            temp=buf[i];
            buf[i]=buf[len];
            buf[len]=temp;
            i++;
            len--;
        }
    }
}
 
int main(int argc, const char *argv[])
{
    pthread_t tid;
    pthread_create(&tid,NULL,func,NULL);
    while(1){
        int i=strcmp(buf,"1234567");
        int j=strcmp(buf,"7654321");
        if(!i||!j){
            printf("主线程: %s\n",buf);                      
        }
    }
    return 0;
}   
                                                             

#include 
#include 
#include 
#include 
#include 
#include 
#include 
 
typedef struct open{
    int fd;
    int fd2;
    off_t size;
}FUN;
 
void* func(void* arg){
    FUN* mode=(FUN*)arg;
    lseek(mode->fd,0,SEEK_SET);
    lseek(mode->fd2,0,SEEK_SET);
    char c;
    for(int i=0;i<(mode->size)/2;i++){
        read(mode->fd,&c,1);
        write(mode->fd2,&c,1);
    }
    printf("前半部分拷贝完成\n");
 
    pthread_exit(NULL);
    return NULL;
}
 
int main(int argc, const char *argv[])
{
    FUN mode;
    mode.fd=open("./1.png",O_RDONLY);
    if(mode.fd<0){
        perror("open");
        return -1;
    }
    mode.fd2=open("./2.png",O_WRONLY|O_CREAT|O_TRUNC,0664);
    if(mode.fd2<0){
        perror("open_fd2");
        return -1;
    }
    mode.size=lseek(mode.fd,0,SEEK_END);
    pthread_t tid;
    pthread_create(&tid,NULL,func,(void*)&mode);
 
    pthread_join(tid,NULL);
    char c;
    //lseek(mode.fd,(mode.size)/2,SEEK_SET);
    //lseek(mode.fd2,(mode.size)/2,SEEK_SET);                                           
    for(int i=(mode.size)/2;i
        read(mode.fd,&c,1);
        write(mode.fd2,&c,1);
    }
    printf("全部拷贝完成\n");
    return 0;
}