函数名: rewind
功 能: 将文件指针重新指向一个流的开头
用 法: int rewind(FILE *stream);
头文件：stdio.h
返回值：成功返回0，失败返回其它值
英文解释： A statement such as
rewind( cfptr );
causes a program's file position--which indicates the number of the next byte in the file to be read or written-- to be repositioned to the beginnning of the file pointed to by cfptr.
程序例:
#include <stdio.h>
#include <dir.h>
int main(void)
{
FILE *fp;
char fname[10] = "TXXXXXX", *newname, first;
newname = mktemp(fname);
fp = fopen(newname,"w+");
if(NULL==fp)
return 1;
fprintf(fp,"abcdefghijklmnopqrstuvwxyz");
rewind(fp);
fscanf(fp,"%c",&first);
printf("The first character is: %c
",first);
fclose(fp);
remove(newname);
return 0;
}