Visual Basic Help for making a simple calculator
对名为calculateResult的函数过程进行编码，该过程执行请求的操作并返回十进制值。此函数应接受以下参数：decoperAnd1为十进制-为第一个操作数输入的值。strOperator作为字符串-这四个运算符之一：+、-、*或/。decopperand2 as decimal-为第二个操作数输入的值。
这是我需要的代码，任何可以提供的帮助都将不胜感激。
可能的编码解决方案：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | REM Code a Function procedure named CalculateResult that performs the REM requested operation and returns a decimal value. This function should REM accept the following parameters: decOperand1 As Decimal - The value REM entered for the first operand. strOperator As String - One of these REM four operators: +, -, *, or /. decOperand2 As Decimal - The value REM entered for the second operand. PRINT"Enter value1";: INPUT decOperand1& PRINT"Enter operand(+,-,*,/,^)";: INPUT strOperator$ PRINT"Enter value2";: INPUT decOperand2& PRINT"Result"; CalculateResult(decOperand1&, strOperator$, decOperand2&) END FUNCTION CalculateResult (decOperand1&, strOperator$, decOperand2&) SELECT CASE strOperator$ CASE"+","+=" CalculateResult = decOperand1& + decOperand2& CASE"-","-=" CalculateResult = decOperand1& - decOperand2& CASE"*","*=" CalculateResult = decOperand1& * decOperand2& CASE"/","/=" CalculateResult = decOperand1& / decOperand2& CASE"^","^=" CalculateResult = decOperand1& ^ decOperand2& CASE ELSE PRINT"Unknown operator." END SELECT END FUNCTION |
这是QB45、QB64中一个成熟的递归下降解析器：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 | REM File: Recursive descent parser 2019. DIM SHARED Out2 AS STRING DIM SHARED Token AS INTEGER DIM SHARED Token1 AS STRING DIM SHARED Token2 AS STRING DIM SHARED Token.Index AS INTEGER DO COLOR 15, 0 PRINT"Equation";: INPUT Out2 IF Out2 ="" THEN EXIT DO COLOR 14, 0 PRINT"Equals:"; Equate(Out2) LOOP COLOR 7, 0 END FUNCTION Equate (Out2$) Temp# = DFalse Var = INSTR(Out2$,"") WHILE Var Out2$ = LEFT$(Out2$, Var - 1) + MID$(Out2$, Var + 1) Var = INSTR(Out2$,"") WEND IF Out2$ <>"" THEN Out2$ = UCASE$(Out2$) Token.Index = 1 CALL Get.Token CALL Parse1(Temp#) END IF Equate = Temp# END FUNCTION ' logical parser SUB Parse1 (Temp#) CALL Parse2(Temp#) Token.Parsed$ = Token2$ DO SELECT CASE Token.Parsed$ CASE"|","&","~","?",":" Eat$ ="" CASE ELSE EXIT DO END SELECT Token.Stored$ = Token1$ CALL Get.Token CALL Parse2(Temp2#) Token1$ = Token.Stored$ CALL Arith(Token.Parsed$, Temp#, Temp2#) Token.Parsed$ = Token2$ LOOP END SUB ' relational parser SUB Parse2 (Temp#) CALL Parse3(Temp#) Token.Parsed$ = Token2$ DO SELECT CASE Token.Parsed$ CASE"<",">","=","#",">=","<=","<>","^=" Eat$ ="" CASE ELSE EXIT DO END SELECT Token.Stored$ = Token1$ CALL Get.Token CALL Parse3(Temp2#) Token1$ = Token.Stored$ CALL Arith(Token.Parsed$, Temp#, Temp2#) Token.Parsed$ = Token2$ LOOP END SUB ' addition/subtraction parser SUB Parse3 (Temp#) CALL Parse4(Temp#) Token.Parsed$ = Token2$ DO SELECT CASE Token.Parsed$ CASE"+","-" Eat$ ="" CASE ELSE EXIT DO END SELECT Token.Stored$ = Token1$ CALL Get.Token CALL Parse4(Temp2#) Token1$ = Token.Stored$ CALL Arith(Token.Parsed$, Temp#, Temp2#) Token.Parsed$ = Token2$ LOOP END SUB ' modulo parser SUB Parse4 (Temp#) CALL Parse5(Temp#) Token.Parsed$ = Token2$ DO SELECT CASE Token.Parsed$ CASE"%" Eat$ ="" CASE ELSE EXIT DO END SELECT Token.Stored$ = Token1$ CALL Get.Token CALL Parse5(Temp2#) Token1$ = Token.Stored$ CALL Arith(Token.Parsed$, Temp#, Temp2#) Token.Parsed$ = Token2$ LOOP END SUB ' integer division parser SUB Parse5 (Temp#) CALL Parse6(Temp#) Token.Parsed$ = Token2$ DO SELECT CASE Token.Parsed$ CASE"" Eat$ ="" CASE ELSE EXIT DO END SELECT Token.Stored$ = Token1$ CALL Get.Token CALL Parse6(Temp2#) Token1$ = Token.Stored$ CALL Arith(Token.Parsed$, Temp#, Temp2#) Token.Parsed$ = Token2$ LOOP END SUB ' multiplication/division parser SUB Parse6 (Temp#) CALL Parse7(Temp#) Token.Parsed$ = Token2$ DO SELECT CASE Token.Parsed$ CASE"*","/" Eat$ ="" CASE ELSE EXIT DO END SELECT Token.Stored$ = Token1$ CALL Get.Token CALL Parse7(Temp2#) Token1$ = Token.Stored$ CALL Arith(Token.Parsed$, Temp#, Temp2#) Token.Parsed$ = Token2$ LOOP END SUB ' power parser SUB Parse7 (Temp#) CALL Parse7a(Temp#) Token.Parsed$ = Token2$ DO SELECT CASE Token.Parsed$ CASE"^" Eat$ ="" CASE ELSE EXIT DO END SELECT Token.Stored$ = Token1$ CALL Get.Token CALL Parse7a(Temp2#) Token1$ = Token.Stored$ CALL Arith(Token.Parsed$, Temp#, Temp2#) Token.Parsed$ = Token2$ LOOP END SUB ' dual-unary parser SUB Parse7a (Temp#) CALL Parse8(Temp#) Token.Parsed$ = Token2$ DO SELECT CASE Token.Parsed$ CASE"<<",">>","--","++","**","//","||","##","^^" Eat$ ="" CASE ELSE EXIT DO END SELECT Token.Stored$ = Token1$ CALL Get.Token ' CALL Parse8(Temp2#) ' no secondary token Token1$ = Token.Stored$ CALL Arith(Token.Parsed$, Temp#, Temp2#) Token.Parsed$ = Token2$ LOOP END SUB ' not/unary plus/unary negative parser SUB Parse8 (Temp#) Token.Negate$ ="" ' reset token storage Token.Parsed$ = Token2$ ' store token ' process token DO SELECT CASE Token.Parsed$ CASE"!","-","+","--","++" Eat$ ="" CASE ELSE EXIT DO END SELECT CALL Get.Token ' read next token Token.Negate$ = Token.Negate$ + Token.Parsed$ Token.Parsed$ = Token2$ ' store token LOOP CALL Parse9(Temp#) ' get next operator ' process the combined operators FOR Token.Type = LEN(Token.Negate$) TO 1 STEP -1 SELECT CASE MID$(Token.Negate$, Token.Type, 1) ' get next token CASE"+" Eat$ ="" CASE"-" Temp# = -Temp# ' perform negate CASE"!" ' not Temp# = NOT Temp# ' perform not calculation END SELECT NEXT END SUB SUB Parse9 (Temp#) SELECT CASE Token CASE 1 SELECT CASE Token2$ CASE"(" CALL Get.Token IF Token2$ <>")" THEN DO CALL Parse1(Temp#) LOOP UNTIL Token2$ =")" OR Token = False CALL Get.Token END IF CASE")" CALL Get.Token EXIT SUB END SELECT CASE 2 SELECT CASE RIGHT$(Token2$, 1) CASE"H" ' hexidecimal Temp# = DFalse Var = False FOR Var1 = LEN(Token2$) - 1 TO 1 STEP -1 Var2 = VAL("&H" + (MID$(Token2$, Var1, 1))) Temp# = Temp# + Var2 * 16 ^ Var Var = Var + 1 NEXT CASE"O" ' octal Temp# = DFalse Var = False FOR Var1 = LEN(Token2$) - 1 TO 1 STEP -1 Var2 = VAL(MID$(Token2$, Var1, 1)) Temp# = Temp# + Var2 * 8 ^ Var Var = Var + 1 NEXT CASE"B" ' binary Temp# = DFalse Var = False FOR Var1 = LEN(Token2$) - 1 TO 1 STEP -1 IF MID$(Token2$, Var1, 1) ="1" THEN Temp# = Temp# + 2 ^ Var END IF Var = Var + 1 NEXT CASE ELSE ' decimal Temp# = VAL(Token2$) END SELECT CALL Get.Token CASE 3 SELECT CASE Token2$ CASE"RND" Temp# = RND CASE"ABS" CALL Get.Token CALL Get.Token CALL Parse1(Temp#) Temp# = ABS(Temp#) CASE"NOT" CALL Get.Token CALL Get.Token CALL Parse1(Temp#) Temp# = NOT (Temp#) CASE"SGN" CALL Get.Token CALL Get.Token CALL Parse1(Temp#) Temp# = SGN(Temp#) CASE"SQR" CALL Get.Token CALL Get.Token CALL Parse1(Temp#) Temp# = SQR(Temp#) CASE"OR" CALL Get.Token CALL Get.Token CALL Parse1(Temp#) Number# = Temp# CALL Get.Token CALL Parse1(Temp#) Temp# = Number# OR Temp# CASE"AND" CALL Get.Token CALL Get.Token CALL Parse1(Temp#) Number# = Temp# CALL Get.Token CALL Parse1(Temp#) Temp# = Number# AND Temp# CASE"EQV" CALL Get.Token CALL Get.Token CALL Parse1(Temp#) Number# = Temp# CALL Get.Token CALL Parse1(Temp#) Temp# = Number# EQV Temp# CASE"IMP" CALL Get.Token CALL Get.Token CALL Parse1(Temp#) Number# = Temp# CALL Get.Token CALL Parse1(Temp#) Temp# = Number# IMP Temp# CASE"MOD" CALL Get.Token CALL Get.Token CALL Parse1(Temp#) Number# = Temp# CALL Get.Token CALL Parse1(Temp#) Temp# = Number# MOD Temp# CASE"XOR" CALL Get.Token CALL Get.Token CALL Parse1(Temp#) Number# = Temp# CALL Get.Token CALL Parse1(Temp#) Temp# = Number# XOR Temp# END SELECT CALL Get.Token END SELECT END SUB SUB Arith (Token.Parsed$, Temp#, Temp2#) SELECT CASE Token.Parsed$ CASE"+" Temp# = Temp# + Temp2# CASE"-" Temp# = Temp# - Temp2# CASE"/" Temp# = Temp# / Temp2# CASE"" Temp# = Temp# \ Temp2# CASE"*" Temp# = Temp# * Temp2# CASE"^" Temp# = Temp# ^ Temp2# CASE"<" Temp# = Temp# < Temp2# CASE">" Temp# = Temp# > Temp2# CASE"<<" Temp# = Temp# * 2# CASE">>" Temp# = Temp# \ 2# CASE"||" Temp# = Temp# * 10# CASE"##" Temp# = Temp# \ 10# CASE"^^" Temp# = Temp# ^ 10# CASE"++" Temp# = Temp# + 1# CASE"--" Temp# = Temp# - 1# CASE"**" Temp# = Temp# ^ 2# CASE"//" Temp# = SQR(Temp#) CASE"=" Temp# = Temp# = Temp2# CASE"<=" Temp# = Temp# <= Temp2# CASE">=" Temp# = Temp# >= Temp2# CASE"#","<>" Temp# = Temp# <> Temp2# CASE"^=" Temp# = Temp# ^ Temp2# CASE"|" Temp# = Temp# OR Temp2# CASE"&" Temp# = Temp# AND Temp2# CASE"%" Temp# = Temp# MOD Temp2# CASE"~" Temp# = Temp# XOR Temp2# CASE"?" Temp# = Temp# IMP Temp2# CASE":" Temp# = Temp# EQV Temp2# END SELECT END SUB SUB Get.Token Token.List$ =" -+*/\^()[]{}<>=#|&!%~?:," Token2$ ="" Token = False IF Token.Index > LEN(Out2) THEN Token2$ ="" EXIT SUB END IF CALL Get.Token2(Token.Exists) IF Token.Exists THEN EXIT SUB END IF Token.Element$ = MID$(Out2, Token.Index, 1) IF LEN(Token.Element$) THEN IF INSTR(Token.List$, Token.Element$) THEN Token = 1 Token2$ = Token.Element$ Token.Index = Token.Index + 1 EXIT SUB END IF END IF Token.Element$ = MID$(Out2, Token.Index, 1) IF (Token.Element$ >="0" AND Token.Element$ <="9") OR Token.Element$ ="." THEN DO IF LEN(Token.Element$) = False THEN EXIT DO END IF IF INSTR(Token.List$, Token.Element$) THEN EXIT DO END IF Token2$ = Token2$ + Token.Element$ Token.Index = Token.Index + 1 Token.Element$ = MID$(Out2, Token.Index, 1) LOOP Token = 2 EXIT SUB END IF Token.Element$ = MID$(Out2, Token.Index, 1) IF Token.Element$ >="A" AND Token.Element$ <="Z" THEN DO IF LEN(Token.Element$) = False THEN EXIT DO END IF IF INSTR(Token.List$, MID$(Out2, Token.Index, 1)) THEN EXIT DO END IF Token2$ = Token2$ + Token.Element$ Token.Index = Token.Index + 1 Token.Element$ = MID$(Out2, Token.Index, 1) LOOP Token = 3 EXIT SUB END IF END SUB ' tokens of length 2 SUB Get.Token2 (Token.Exists) Token.Exists = False Next.Token$ = MID$(Out2, Token.Index, 2) SELECT CASE Next.Token$ CASE"||" Token = 1 Token2$ ="||" Token.Index = Token.Index + 2 Token.Exists = True CASE"##" Token = 1 Token2$ ="##" Token.Index = Token.Index + 2 Token.Exists = True CASE"<<" Token = 1 Token2$ ="<<" Token.Index = Token.Index + 2 Token.Exists = True CASE">>" Token = 1 Token2$ =">>" Token.Index = Token.Index + 2 Token.Exists = True CASE"--" Token = 1 Token2$ ="--" Token.Index = Token.Index + 2 Token.Exists = True CASE"++" Token = 1 Token2$ ="++" Token.Index = Token.Index + 2 Token.Exists = True CASE"**" Token = 1 Token2$ ="**" Token.Index = Token.Index + 2 Token.Exists = True CASE"//" Token = 1 Token2$ ="//" Token.Index = Token.Index + 2 Token.Exists = True CASE">=","=>" Token = 1 Token2$ =">=" Token.Index = Token.Index + 2 Token.Exists = True CASE"<=","=<" Token = 1 Token2$ ="<=" Token.Index = Token.Index + 2 Token.Exists = True CASE"<>","><" Token = 1 Token2$ ="<>" Token.Index = Token.Index + 2 Token.Exists = True CASE"^=" Token = 1 Token2$ ="^=" Token.Index = Token.Index + 2 Token.Exists = True CASE"^^" Token = 1 Token2$ ="^^" Token.Index = Token.Index + 2 Token.Exists = True END SELECT END SUB |
附加解析函数：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | REM Code a Function procedure named CalculateResult that performs the REM requested operation and returns a decimal value. This function should REM accept the following parameters: decOperand1 As Decimal - The value REM entered for the first operand. strOperator As String - One of these REM four operators: +, -, *, or /. decOperand2 As Decimal - The value REM entered for the second operand. PRINT"Enter value1";: INPUT decOperand1& PRINT"Enter operand(+,-,*,/,^)";: INPUT strOperator$ PRINT"Enter value2";: INPUT decCalc2$ IF decCalc2$ ="" THEN PRINT"Result:"; CalculateResult2(decOperand1&, strOperator$) ELSE decOperand2& = VAL(decCalc2$) PRINT"Result:"; CalculateResult(decOperand1&, strOperator$, decOperand2&) END IF END FUNCTION CalculateResult (decOperand1&, strOperator$, decOperand2&) SELECT CASE strOperator$ CASE"+","+=" CalculateResult = decOperand1& + decOperand2& CASE"-","-=" CalculateResult = decOperand1& - decOperand2& CASE"*","*=" CalculateResult = decOperand1& * decOperand2& CASE"/","/=" CalculateResult = decOperand1& / decOperand2& CASE"^","^=" CalculateResult = decOperand1& ^ decOperand2& CASE ELSE PRINT"Unknown operator." END SELECT END FUNCTION FUNCTION CalculateResult2 (decOperand1&, strOperator$) SELECT CASE strOperator$ CASE"++" CalculateResult2 = decOperand1& + 1& CASE"--" CalculateResult2 = decOperand1& - 1& CASE"//" ' shift-left CalculateResult2 = decOperand1& * 2& CASE"**" ' shift-right CalculateResult2 = decOperand1& / 2& CASE ELSE PRINT"Unknown operator." END SELECT END FUNCTION |