汇编区，好冷清啊，远没有c语言那么热闹，发个程序

DATAS SEGMENT
    str db 50 dup (?)
    str1 db 50 dup (?)
DATAS ENDS

CODES SEGMENT
    ASSUME CS:CODES,DS:DATAS
START:
    MOV AX,DATAS
    MOV DS,AX
   
    mov cx,50
    mov bx,0
loops:  mov ah,1h
        int 21h
        cmp al,13
        jz loop1
        mov [str+bx],al
        inc bx
        loop loops
      
loop1:    mov si,0
        mov cx,bx
        dec bx
      
loop2:  mov al,[str+bx]
        mov [str1+si],al
        dec bx
        inc si
        cmp bx,-1
        jz  exit
        loop loop2
               
exit:    mov [str1+si],'$'
        lea dx,str1
        mov ah,9h
        int 21h   
              
    MOV AH,4CH
    INT 21H
CODES ENDS
    END START