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 <stdio.h> #include <process.h> #include <string.h> 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; }
推荐教程:《PHP》