关键词: fwrite使用 linux 心得
fwrite函数
1.函数功能
用来读写一个数据块。
2.一般调用形式
fwrite(buffer,size,count,fp);
3.说明
(1)buffer:是一个指针,对fread来说,它是读入数据的存放地址。对fwrite来说,是要输出数据的地址。
(2)size:要读写的字节数;
(3)count:要进行读写多少个size字节的数据项;
(4)fp:文件型指针
这是工作中用fwrite函数写的例子,不仅记录下自己的学习情况,也分享给各位朋友这个fwrite函数实例。
这个fwrite实例是当前时间写入文本的程序,下面这个是fwrite函数的使用方法。
int markfile(void )
{
FILE *sp;
// charbuff[512] ;
char count =0;
char*currentime = NULL;
char *wday[]= {"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
time_ttimep;
struct tm*p;
time(&timep);
p =localtime(&timep);
currentime =ctime(&timep);
//memset(buff,0,512);
//sprintf(buff,"%s",currentime);
printf("%d/%d/%d",(1900+p->tm_year),(1+p->tm_mon),p->tm_mday);
printf(" %s%d:%d:%dn",wday[p->tm_wday],p->tm_hour,p->tm_min,p->tm_sec);
if((sp =fopen("/root/kay/mark.txt","a+")) == NULL)
return 0;
fwrite(currentime,size(currentime)-1,1,sp);
fclose(sp);
return1;
}
size(currentime)( = 26)的作用是得出指针currentime所指的字符串的个数(包括' '),但是会输出乱码(应该是字符串的个数太长了),因此,我把个数减掉一个,就能舒适正确结果。
用另外一种方法:
int markfile(void )
{
FILE *sp;
charbuff[512] ;
char count =0;
char*currentime = NULL;
char *wday[]= {"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
time_ttimep;
struct tm*p;
time(&timep);
p =localtime(&timep);
currentime =ctime(&timep);
//memset(buff,0,512);
sprintf(buff,"%s",currentime);
printf("%d/%d/%d",(1900+p->tm_year),(1+p->tm_mon),p->tm_mday);
printf(" %s%d:%d:%dn",wday[p->tm_wday],p->tm_hour,p->tm_min,p->tm_sec);
if((sp =fopen("/root/kay/mark.txt","a+")) == NULL)
return 0;
fwrite(currentime,(count = strlen(buff)),1,sp);
printf("%dn",count);
fclose(sp);
return1;
}
count = strlen(buff) 来获得字符的个数 结果是25,
综上的对比 觉得是fwrite()输出的字符不要包括结束符(' '),否则会因为字符个数多了而造成乱码
看完的朋友,觉得对你们有帮助就顶一个,如果觉得哪里不好,可以发表下看法,共同学习。