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C语言“fread”函数的用法为“size_tf read(void *buffer,size_t size,size_t count,FILE *stream)”，其作用是从一个文件流中读数据，读取count个元素，每个元素size字节。
示例1
#include
#include
#include
int main()
{
FILE *stream;
char msg[]=”this is a test”;
char buf[20];
if ((stream=fopen(“dummy.fil”,”w “))==NULL)
{
fprintf(stderr,”cannot open output file.\n”);
return 1;
}
/*write some data to the file*/
fwrite(msg,1,strlen(msg) 1,stream);
/*seek to the beginning of the file*/
fseek(stream,0,SEEK_SET);
/*read the data and display it*/
fread(buf,1,strlen(msg) 1,stream);
printf(“%s\n”,buf);
fclose(stream);
system(“pause”);
return 0;
}
示例2
int main(void)
{
FILE *stream;
char list[30];
int i,numread,numwritten;
/*open file in text mode:*/
if ((stream=fopen(“fread.out”,”w t”))!=NULL)
{
for (i=0;i<25;i )
{
list[i]=(char)(‘z’-i);
}
/*write 25 characters to stram*/
numwritten=fwrite(list,sizeof(char),25,stream);
printf(“Wrote %d items\n”,numwritten);
fclose(stream);
}
else
printf(“Problem opening the file\n”);
if ((stream=fopen(“fread.out”,”r t”))!=NULL)
{
numread=fread(list,sizeof(char),25,stream);
printf(“Number of items read =%d\n”,numread);
printf(“Contents of buffer=%.25s\n”,list);
fclose(stream);
}
else
{
printf(“File could not be opened\n”);
}
system(“pause”);
return 0;
}
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