帮看一下这个程序哪里有错,怎么改

#include<dos.h>
#include<stdio.h>
#include<stdlib.h>
void main(void)
{union REGS inregs,outregs;
struct SREGS segs;

void far handler(void);
unsigned old_segment,old_offset;
inregs.x.ax=0x3505;
intdosx(&inregs,&outregs,&segs);
old_segment=segs.es;
old_offset=outregs.x.bx;
inregs.x.ax=0x2505;
inregs.x.dx=FP_OFF(&handler);
segs.ds=FP_SEG(&handler);
intdosx(&inregs,&outregs,&segs);
While(getchar()!='\n');
{inregs.x.ax=0x2505;
inregs.x.dx=old_offset;
segs.ds=old_segment;
intdosx(&inregs,&outregs,&segs);}
}
void handler(void)
{
_asm(
PUSH AX
PUSH BX
MOV AH,OEH
MOV AL,7
MOV BX,0
INT 10H
POP BX
POP AX
POP BP
IRET
)
}