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python3高级计算器

热度:90   发布时间:2024-02-10 13:42:21.0

def smartArithmetic1():

    #x存储表达式

    #loc记录当前读取位置

    #count用于将括号和括转进行匹配

    #locStart记录被括号括起来的整体的起始位置,locEnd则记录结束位置(不包括那一对括号)

    x = input("input your expression")

    def cal(exp):

        loc = 0

        count = 0

        # 读入第一个数字/整体(被括号括起来的)

        firstNum = exp[loc]

        if firstNum != "(":

            result = int(firstNum)

            loc += 1

        else:

            locStart = loc + 1

            count += 1  # 为了将( 与 ) 进行匹配

            while count != 0:

                loc += 1

                if exp[loc] == "(":

                    count += 1

                elif exp[loc] == ")":

                    count -= 1

            locEnd = loc

            loc += 1

            result = cal(exp[locStart:locEnd])

        while loc < len(exp):

            operator = exp[loc]

            loc += 1

            #完善第一个整体,即若后面有跟*或者/时读进来计算为一个整体

            while operator == "*" or operator =="/":

                secNum = exp[loc]

                if secNum != "(":

                    loc += 1

                else:

                    locStart = loc+1

                    count += 1#为了将( 与 ) 进行匹配

                    while count != 0:

                        loc += 1

                        if exp[loc] == "(":

                            count += 1

                        elif exp[loc] == ")":

                            count -= 1

                    locEnd = loc

                    loc += 1

                    secNum = cal(exp[locStart:locEnd])

                if operator == "*":

                        result = result * int(secNum)

                else:

                        result = result / int(secNum)

                if loc >= len(exp):

                    break

                operator = exp[loc]

                loc += 1

            #加号或者减号

            operator1 = operator

            if loc >= len(exp):

                break

            secNum = exp[loc]

            if secNum != "(":

                secNum = int(secNum)

                loc += 1

            else:

                locStart = loc + 1

                count += 1  # 为了将( 与 ) 进行匹配

                while count != 0:

                    loc += 1

                    if exp[loc] == "(":

                        count += 1

                    elif exp[loc] == ")":

                        count -= 1

                locEnd = loc

                loc += 1

                secNum = cal(exp[locStart:locEnd])

            #完善第二个加数/减数

            if loc < len(exp):

                operator = exp[loc]

                loc += 1

                flag = False

                while operator == "*" or operator =="/":

                    flag = True

                    thirdNum = exp[loc]

                    if thirdNum != "(":

                        loc += 1

                    else:

                        locStart = loc+1

                        count += 1#为了将( 与 ) 进行匹配

                        while count != 0:

                            loc += 1

                            if exp[loc] == "(":

                                count += 1

                            elif exp[loc] == ")":

                                count -= 1

                        locEnd = loc

                        loc += 1

                        thirdNum = cal(exp[locStart:locEnd])

                    if operator == "*":

                        secNum = secNum * int(thirdNum)

                    else:

                        secNum = secNum / int(thirdNum)

                    if loc >= len(exp):

                        break

                    operator = exp[loc]

                    loc += 1

                if not flag:

                    loc -= 1

            if operator1 == "+":

                result += int(secNum)

            else:

                result -= int(secNum)

            if loc >= len(exp):

                break

        return result

    return cal(x)

qqq=smartArithmetic1()

print(qqq)