海口网站制作方案,php多用户商城双端app,重庆网站建设网站建设,优设网页官网fread()函数---- Reads data from a stream. #includestdio.h size_t fread( void *buffer, size_t size, size_t count,FILE *stream ); 从一个文件流中读数据,读取count个元素,每个元素size字节.如果调用成功返回count.如果调用成功则实际读取size*count字节 buffer… fread()函数---- Reads data from a stream. #includestdio.h size_t fread( void *buffer, size_t size, size_t count,FILE *stream ); 从一个文件流中读数据,读取count个元素,每个元素size字节.如果调用成功返回count.如果调用成功则实际读取size*count字节 buffer的大小至少是 size*count 字节. return: fread returns the number of full items actually read 实际读取的元素数.如果返回值与count(不是count*size)不相同,则可能文件结尾或发生错误. 从ferror和feof获取错误信息或检测是否到达文件结尾.DEMO: [cpp] view plaincopy #include stdio.h #include process.h #include string.h int main() { FILE *stream; char msg[]this is a test; char buf[20]; if ((streamfopen(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; } DEMO2 [cpp] view plaincopy int main(void) { FILE *stream; char list[30]; int i,numread,numwritten; /*open file in text mode:*/ if ((streamfopen(fread.out,wt))!NULL) { for (i0;i25;i) { list[i](char)(z-i); } /*write 25 characters to stram*/ numwrittenfwrite(list,sizeof(char),25,stream); printf(Wrote %d items\n,numwritten); fclose(stream); } else printf(Problem opening the file\n); if ((streamfopen(fread.out,rt))!NULL) { numreadfread(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; } 【FROM MSDN 百科】
