int fseek(FILE *stream, long offset, int fromwhere);
SEEK_SET
:檔案開頭
SEEK_CUR
:現在檔案指標位置
SEEK_END
:檔案結尾
[dywang@dyw219 zzz]$ vim fileio5.c [dywang@dyw219 zzz]$ cat fileio5.c #include <stdio.h> int main( int argc, char *argv[] ) { FILE *fp1; char ch; fp1 = fopen( argv[1], "r" ); if( fp1 != NULL) { while( (ch=fgetc(fp1)) != EOF ) printf("%c", ch); fseek(fp1, 2, SEEK_SET); while( (ch=fgetc(fp1)) != EOF ) printf("%c", ch); } else { printf("File %s does not exist.\n", argv[1]); } fclose(fp1); return 0; }
[dywang@dyw219 zzz]$ gcc -o fileio5 fileio5.c
[dywang@dyw219 zzz]$ echo 'abc 123' > fio5test [dywang@dyw219 zzz]$ cat fio5test abc 123
[dywang@dyw219 zzz]$ ./fileio5 fio5test abc 123 c 123