IO线程-day2

1> 使用fread和fwrite完成两个文件的拷贝

程序：

#define MAXSIZE 1024
#include<myhead.h>

int main(int argc, char const *argv[])
{
    FILE *srcfp=NULL;
    FILE *destfp=NULL;
    if(!(srcfp=fopen("pm.bmp","r")))
        PRINT_ERR("");
    if(!(destfp=fopen("pm1.bmp","w")))
        PRINT_ERR("");
    char buf[MAXSIZE];
    int ret=0;
    while((ret = fread(buf, 1, sizeof(buf), srcfp))!= 0)
	{
		fwrite(buf, 1, ret, destfp);
	}
    fclose(srcfp);
    fclose(destfp);
    return 0;
}

结果：

2> 使用read、write完成两个文件的拷贝

程序：


#define MAXSIZE 1024
#include<myhead.h>

int main(int argc, char const *argv[])
{

    int srcfd=-1;
    int destfd=-1;
    if(!(srcfd=open("./pm.bmp",O_RDONLY)))
        PRINT_ERR("");
    if(!(destfd=open("./pm2.bmp",O_WRONLY|O_CREAT|O_TRUNC,0664)))
        PRINT_ERR("");
    char buf[MAXSIZE];
    int ret=0;
    while((ret = read(srcfd,buf,sizeof(buf)-1))!= 0)
	{
		write(destfd,buf,ret);
        memset(buf,0,sizeof(buf));
	}
    close(srcfd);
    close(destfd);
    return 0;
}

结果：

3> 将时间在文件中跑起来

程序：

#define MAXSIZE 1024
#include<myhead.h>

int linecount(){
    FILE *fp1=NULL;
    if(!(fp1=fopen("test.txt","r")))
        PRINT_ERR("");
    int line=1;
    char buf[MAXSIZE];
    while(1){
        fgets(buf,sizeof(buf),fp1);
        for(int i=0;i<strlen(buf);i++){
            if(buf[i]=='\n')
                line++;
        }
        if(strlen(buf)==0)
            break;
        memset(buf,0,sizeof(buf));
    }
    fclose(fp1);
    return line;
}
int main(int argc, char const *argv[])
{
    int fp = -1;
    if((fp = open("test.txt", O_WRONLY|O_APPEND|O_CREAT)) == -1)
    {
        perror("open error");
        return -1;
    }

    time_t sysTime = time(NULL);
    struct tm* t = localtime(&sysTime);
    char time_buf[128];
    snprintf(time_buf, sizeof(time_buf), "%2d、%2d:%2d:%2d\n", linecount(),t->tm_hour, t->tm_min, t->tm_sec);
    write(fp, time_buf, strlen(time_buf));
    
    int sec = t->tm_sec;
    while (1)
    {
        sysTime = time(NULL);
        t = localtime(&sysTime);

        if (t->tm_sec != sec)
        {
            printf("%s\n", time_buf);
            sec = t->tm_sec;
            snprintf(time_buf, sizeof(time_buf), "%2d、%2d:%2d:%2d\n", linecount(),t->tm_hour, t->tm_min, t->tm_sec);
            write(fp, time_buf, strlen(time_buf));
        }
    }

    close(fp);

    return 0;
}

结果：