简单的计算器模拟程序的设计和实现

1、.简单的计算器模拟程序的设计和实现1.问题描述对任意给定的正确四则运算表达式，程序计算其结果值并输出。程序无需查错功能，假定所输入的都是正确的四则运算表达式，并且表达式中运算分量均为无正负号整数，运算符为 +、-、*、/，表达式以字符 "=" 结束。程序应有操作提示、输入和输出，界面追求友好，最好是菜单式的界面。2.设计说明2.1简要的分析根据要求，要先输入包含有+，-，*，/的运算符的表达式，然后经过计算得到正确的答案。从键盘中输入的是ASCII码，因此要将其转换为十进制的数据然后才能进行计算。如果输入混合表达式，要将中缀式先变化成后缀式，然后再进行计算。2.2概要分析2

2、.2.1 定义的数据段用于定义一些中间变量，并将显示在试验界面上，以及提示信息。data segment stri db 50 dup(0) exp db 30 dup(0) track db 30 dup(0) instr db 100 dup(0) msg0 db 'please input your formular:',0dh,0ah,'$' msg1 db 0dh,0ah,'wrong input','$' msg2 db 0dh,0ah,') and ( does not match','$&#

3、39; msg3 db 0dh,0ah,'div zero error','$' msg4 db 0dh,0ah,'sorry,minus data appears','$' msg5 db 0dh,0ah,'any key to continue,esc to exit','$' data ends 2.2.2 定义的堆栈段声明用于将中缀表达式转换为后缀表达式，以及进行后缀表达式求值过程用到的堆栈段。stack segment para stack dw 256 dup(0) stack ends

4、 2.2.3 用到的子过程2.2.3.1 compare子过程作用：用于判断键盘输入的符号是否合法，若合法，则在屏幕上显示，否则报错。2.2.3.2 mult子过程作用：用于对输入的数字进行乘10累加操作，以便将连续输入的数字字符串转换为相对应的数值。2.2.3.3 trans子过程作用：将输入的中缀表达式转换为后缀表达式。2.2.3.4 value子过程作用：将后缀表达式结合堆栈结构进行表达式求值。2.2.3.5 divi子过程作用：通过除以10以及进一步处理将某数值转换为相应的ASCII字符串。2.2.3.6 print子过程作用：将表达式求值结果输出到屏幕上。3.详细的算法描述3.1.程

5、序运行流程代码段开始Main过程，接收输入，并处理表达式Trans子过程处理将中缀式转换为后缀式Value子过程，计算后缀式Print子过程，转换计算结果，输入到DOS返回DOS3.2程序代码STACK SEGMENT PARA STACK DW 256 DUP(0) STACK ENDS DATA SEGMENT STRI DB 50 DUP(0) EXP DB 30 DUP(0) TRACK DB 30 DUP(0) INSTR DB 100 DUP(0) MSG0 DB 'please input the formular:',0DH,0AH,'$' MS

6、G1 DB 0DH,0AH,'sorrry,wrong input','$' MSG2 DB 0DH,0AH,') and ( does not match','$' MSG3 DB 0DH,0AH,'div by zero error','$' MSG4 DB 0DH,0AH,'sorry,minus data appears','$' MSG5 DB 0DH,0AH,'any key to continue,esc to exit','$&

7、#39; DATA ENDS CODE SEGMENT ASSUME CS:CODE,SS:STACK,DS:DATA START: MOV AX,STACK MOV SS,AX MOV AX,DATA MOV DS,AX MOV DX,OFFSET MSG0 MOV AH,9 INT 21H XOR AX,AX ;READ MOV BX,OFFSET INSTR MOV DL,20H JMP L2 COMPARE PROC NEAR CMP AL,0DH JZ L2 MOV DL,AL MOV AH,2 INT 21H RET COMPARE ENDP L2: MOV AH,8 INT 21

8、H CALL COMPARE CMP AL,3DH ;end with '=' JZ L2_OVER MOV AH,39H CMP AH,AL ;del the wrong data ( > 9 ) JNB CONTI MOV AH,2 MOV DL,8 INT 21H MOV DL,20H INT 21H MOV DL,8 INT 21H JMP L2 CONTI: CMP AL,28H ;'(' JZ L2_YES CMP AL,29H JZ L2_YES ;')' CMP AL,2AH ;'*' JZ L2_YES C

9、MP AL,2BH ; '+' JZ L2_YES CMP AL,2DH ; '-' JZ L2_YES CMP AL,2FH ; '/' JZ L2_YES ; back function ' <- ' CMP AL,08H JNZ NO_8 L2_NEXT: PUSH DX MOV DL,20H MOV AH,2 INT 21H MOV DL,8 MOV AH,2 INT 21H CMP BX,OFFSET INSTR JZ L2 DEC BX MOV AL,0 MOV BX,AL POP DX JMP L2 ; NO_

10、8: MOV AH,2FH CMP AH,AL ;del the wrong data ( < 0 ) JB L2_YES MOV AH,2 MOV DL,8 INT 21H MOV DL,20H INT 21H MOV DL,8 INT 21H JMP L2 L2_YES: MOV DH,DL MOV DL,AL CMP DL,20H JNZ L2_NO20 CMP DH,20H JZ L2 L2_NO20: MOV BX,AL INC BX JMP L2 L2_OVER: MOV AH,3DH MOV BX,AH;check input MOV SI,OFFSET INSTR MOV

11、 AH,30H MOV CH,0 ;record ( ) MOV CL,0 L3: MOV AL,SI INC SI CMP AL,3DH JZ L3_OVER CMP AL,2AH JNB MAY_WRONG CMP AL,29H JZ L3_29 INC CH JMP L3_RIGHT L3_29: INC CL JMP L3_RIGHT MAY_WRONG: CMP AL,30H JNB L3_RIGHT CMP AL,28H JZ L3_RIGHT CMP AH,29H JZ L3_RIGHT ;cmp ah,28h ;jz L3_right CMP AH,30H JNB L3_RIG

12、HT MOV DX,OFFSET MSG1 MOV AH,9 INT 21H JMP OVER3 L3_RIGHT: MOV AH,AL JMP L3 L3_OVER: CMP CH,CL JZ INPUT_WRIGHT MOV DX,OFFSET MSG2 MOV AH,9 INT 21H JMP OVER3 ; ;chech over INPUT_WRIGHT: MOV BX,OFFSET STRI MOV SI,OFFSET INSTR ;read READ: ;mov ah,1 ;int 21h MOV AL,SI ;reserve the data by decimaltest IN

13、C SI MOV AH,28H ;( CMP AH,AL JZ IN_STRI MOV AH,29H ;) CMP AH,AL JZ IN_STRI MOV AH,2AH ;* CMP AH,AL JZ IN_STRI MOV AH,2BH ;+ CMP AH,AL JZ IN_STRI MOV AH,2DH ;- CMP AH,AL JZ IN_STRI MOV AH,2FH ;/ CMP AH,AL JZ IN_STRI MOV AH,2FH ;delete the wrong input CMP AH,AL JNB READ MOV AH,3DH ;= CMP AH,AL JZ IN_S

14、TRI MOV AH,39H ;delete the wrong input CMP AH,AL JB READ CALL NEAR PTR MULT JMP READ ; the end of reserve ; IN_STRI: MOV AH,0 CMP AH,BX JZ NO_BX ;inc bx INC BX NO_BX: MOV BX,AL MOV AH,3DH CMP AH,AL JNZ NO_OVER SUB AL,25 ;transplant '=' to '$' MOV BX,AL JMP OVER NO_OVER: JMP READ MULT

15、 PROC NEAR ;mult data*10,add up PUSH DX PUSH CX PUSH AX MOV AH,0 CMP BX,AH JZ NO_INC_BX MOV AH,30H CMP BX,AH JNB NO_INC_BX INC BX NO_INC_BX: MOV DX,0 MOV CX,10 MOV AH,BX CMP AH,30H JB NO_SUB SUB AH,30H NO_SUB: MOV BX,AH NEXT: ADD DX,BX LOOP NEXT SUB AL,30H ;tras to decimal ADD DL,AL MOV BX,DL MOV AH

16、,BX ADD AH,30H MOV BX,AH POP AX POP CX POP DX RET MULT ENDP ; ;end of read OVER: CALL NEAR PTR TRANS ;the outlet of the program OVER1: CALL NEAR PTR VALUE ;jmp instead of ret in procedure trans OVER2: CALL NEAR PTR PRINT OVER3: MOV AH,9 MOV DX,OFFSET MSG5 INT 21H MOV AH,8 INT 21H CMP AL,1BH JZ OVER4

17、 MOV CX,210 MOV BX,OFFSET STRI MOV AL,0 OVER_LOOP: MOV BX,AL INC BX LOOP OVER_LOOP MOV AH,2 MOV DL,0DH INT 21H MOV DL,0AH INT 21H JMP START OVER4: MOV AH,4CH INT 21H ; ;trans TRANS PROC NEAR ; PUSH AX PUSH BX PUSH CX PUSH DX PUSH SI PUSH DI XOR CX,CX MOV BX,OFFSET STRI MOV SI,OFFSET EXP MOV DI,OFFSE

18、T TRACK TRANS_WHILE: MOV AL,BX INC BX MOV AH,24H ;'$' CMP AH,AL JZ TRANS_OVER ;end with '=' MOV AH,2FH ;judge L digital CMP AH,AL JNB NO_DIGITAL MOV SI,AL INC SI JMP TRANS_WHILE NO_DIGITAL: MOV AH,28H ;judge L '(' CMP AH,AL JNZ NO_9 MOV DI,AL ;push al INC DI JMP TRANS_WHILE N

19、O_9: MOV AH,29H ;judge L ')' CMP AH,AL JNZ NO_0 POP_WHILE: DEC DI MOV AL,DI ; pop al MOV AH,28H CMP AH,AL JZ OVER_POP_WHILE MOV SI,AL INC SI JMP POP_WHILE OVER_POP_WHILE: ;mov al,dl JMP TRANS_WHILE NO_0: MOV AH,2BH CMP AH,AL JZ OR1_YES MOV AH,2DH CMP AH,AL ;if al is '+' or '-'

20、; JNZ NO_OR1 OR1_YES: CMP DI,OFFSET TRACK ;jmp if stack is blank JZ STACK_BLANK DEC DI ;pop al MOV CL,DI MOV AH,28H CMP AH,CL JZ OVER_OR1_YES MOV SI,CL INC SI JMP OR1_YES OVER_OR1_YES: MOV DI,CL INC DI ;reserve the ')' STACK_BLANK: MOV DI,AL ;push al INC DI JMP TRANS_WHILE NO_OR1: MOV AH,2AH

21、 CMP AH,AL JZ OR2_YES MOV AH,2FH CMP AH,AL JNZ NO_OR2 ;if al is '*' or '/' OR2_YES: DEC DI ;push dl MOV CL,DI MOV AH,2AH CMP AH,CL JZ OR2_YES_OR MOV AH,2FH CMP AH,CL JNZ OR2_OVER OR2_YES_OR: MOV SI,CL INC SI JMP OR2_YES OR2_OVER: MOV DI,CL INC DI ;push al MOV DI,AL INC DI NO_OR2: ;mo

22、v al,bx ;inc bx ; JMP TRANS_WHILE TRANS_OVER: CMP DI,OFFSET TRACK JZ POP_OVER DEC DI MOV AL,DI MOV SI,AL INC SI JMP TRANS_OVER POP_OVER: MOV AL,24H ;end with '=' MOV SI,AL POP DI POP SI POP DX POP CX POP BX POP AX JMP OVER1 TRANS ENDP ; end of trans ;start value VALUE PROC NEAR ;get the valu

23、e PUSH AX PUSH BX PUSH CX PUSH DX PUSH SI MOV BX,OFFSET EXP MOV SI,OFFSET TRACK XOR AX,AX VALUE_WHILE: MOV AL,BX INC BX MOV AH,24H CMP AH,AL JZ VALUE_OVER MOV AH,2FH ;judge L digital CMP AH,AL JNB VALUE_NO_DIGITAL SUB AL,30H MOV SI,AL INC SI JMP VALUE_WHILE VALUE_NO_DIGITAL: MOV AH,2BH ;+ CMP AH,AL

24、JNZ NO_ADD DEC SI MOV DL,SI DEC SI MOV DH,SI ADD DH,DL MOV SI,DH INC SI JMP VALUE_WHILE NO_ADD: MOV AH,2DH ;- CMP AH,AL JNZ VALUE_NO_SUB DEC SI MOV DL,SI DEC SI MOV DH,SI CMP DH,DL JNB SUB_RIGHT MOV DX,OFFSET MSG4 MOV AH,9 INT 21H JMP OVER3 SUB_RIGHT: SUB DH,DL MOV SI,DH INC SI JMP VALUE_WHILE VALUE

25、_NO_SUB: MOV AH,2AH ;* CMP AH,AL JNZ NO_MUL DEC SI MOV DH,SI DEC SI MOV AL,SI MUL DH MOV SI,AL INC SI JMP VALUE_WHILE NO_MUL: MOV AH,2FH ;/ CMP AH,AL JNZ NO_DIV DEC SI MOV DH,SI DEC SI MOV AL,SI XOR AH,AH CMP DH,0 JNZ DIV_RIGHT MOV DX,OFFSET MSG3 MOV AH,9 INT 21H JMP OVER3 DIV_RIGHT: DIV DH MOV SI,A

26、L INC SI NO_DIV: JMP VALUE_WHILE ; VALUE_OVER: POP SI POP DX POP CX POP BX POP AX RET VALUE ENDP ; end value procedure ; ;start print PRINT PROC NEAR PUSH AX PUSH DX ;mov dl,al ;mov ah,2 ;int 21h ;mov dl,0dh ;mov ah,2 ;int 21h ;mov dl,0ah ;mov ah,2 ;int 21h MOV BX,OFFSET TRACK CALL NEAR PTR DIVI DEC

27、 AL OK: POP DX POP AX RET PRINT ENDP ;end of print ; DIVI PROC NEAR ;div data/10 funtion:print the data PUSH BX PUSH AX PUSH DX MOV AL,BX XOR AH,AH XOR CX,CX NEXT1: MOV BL,0AH DIV BL MOV DL,AH ADD DL,30H XOR DH,DH PUSH DX INC CX MOV DH,0H ;judge L the end CMP DH,AL JNB DIVI_OVER1 XOR AH,AH JMP NEXT1 DIVI_OVER1: POP DX MOV AH,2 INT 21H LOOP DIVI_OVER1 MOV DL,20H MOV AH,2 INT 21H POP DX POP AX POP BX RET DI