dele.asm

成绩数据库管理系统. 1．能够实现菜单显示、菜单选择、编辑（录入、插入、修改、删除等）、查找、显示、求总成绩、按总成绩排序（高→低）并显示、装入数据文件、数据文件存盘、退出、为数据动态分配存储空间[

INCLUDE filefuc.mac
PUBLIC DELE
GRADES STRUC
STUDENTNUMBER   DB 10 DUP(' ')
               DB '$'
NAM           DB 6 DUP(' ')
               DB '$'
COURSE1          DB 3 DUP(' ')
               DB '$'
COURSE2        DB 3 DUP(' ')
               DB '$'
COURSE3        DB 3 DUP(' ')
               DB '$'
COURSE4        DB 3 DUP(' ')
               DB '$'
SUM         DB 3 DUP(' ')
               DB '$'
LIST          DB 3 DUP(' ')
               DB '$'

GRADES ENDS
DATA SEGMENT
 FILENAME DB 'F:\first.txt',0
CT  EQU $-BUFFER
FILEHANDLE DW 0   ;此处输入数据段代码  
PAGES DW ?
NOS GRADES<>
HANG DB 34
MM DW ?
BUFS DB 1020 DUP(' ') 
DATA ENDS
STSG SEGMENT STACK 'S'
	DW 32 DUP(?)
STSG ENDS
CODE SEGMENT
	  ASSUME CS:CODE,DS:DATA,SS:STSG
DELE PROC FAR;删除当前光标所在记录
     PUSHREG
     push ds
     LOADDS DATA
     MOV PAGES,BX
     
     MOV MM,0
    OPENFILE FILENAME,FILEHANDLE;打开文件
    PUSHREG
    READFILE 1020,BUFS,FILEHANDLE;读取文件
    POPREG
    CURSORPOS
     MOV AL,DH
      MUL HANG
       MOV BX,AX
      ADD MM,BX
     MOV AX,PAGES
    MOV BX,340
     MUL BX
     ADD MM,AX
     MOV BX,MM
     PUSH CX 
     MOV CX,30
     PUSH DX
     MOV DL,DH
     MOV DH,0
     MOV AX,PAGES
     MOV BX,10
     MUL BX
     ADD DX,AX
      SUB CX,DX
     POP DX
R1:   PUSH CX
      MOV CX,30
R2:   MOV AL,BUFS[BX] 
      MOV AH,BUFS[BX+34]
      MOV BUFS[BX],AH
      MOV BUFS[BX+34],AL
      INC BX
      LOOP R2
     POP CX
     ADD BX,3
     LOOP R1
     POP CX
    PUSH CX
      MOV CX,30
      MOV AL,' '
R3:  MOV BUFS[BX],AL 
     INC BX
     LOOP R3
       POP CX
CLOSEFILE FILEHANDLE
OPENFILE FILENAME,FILEHANDLE
WRITEFILE 1020,BUFS,FILEHANDLE;将删除后的记录重新写入文件
    CLOSEFILE FILEHANDLE
    MOV DX,CX
    MOV DL,2;覆盖删除行记录，将其显示为空格
     PUTS DH,DL,NOS.STUDENTNUMBER,1EH
     ADD DL,13
     PUTS DH,DL,NOS.NAM ,1EH
     ADD DL,10
    PUTS DH,DL,NOS.COURSE1,1EH
     ADD DL,10
     PUTS DH,DL,NOS.COURSE2,1EH
      ADD DL,10
    PUTS DH,DL,NOS.COURSE3,1EH
     ADD DL,10
   PUTS DH,DL,NOS.COURSE4,1EH
     ADD DL,10
     PUTS DH,DL,NOS.SUM,1EH
     ADD DL,10
     PUTS DH,DL,NOS.LIST,1EH
     MOV DH,CH 
      MOV DL,CL
      CURSOR
      pop ds     
    POPREG
       RET 
DELE ENDP       
CODE ENDS
    END DELE