수식 계산기, 파서 트리, 컴파일러 이론 접목(어휘분석, 구문분석,파싱) [C++ 소스]

수식 계산기, 파서 트리

컴파일러 이론 접목(어휘분석, 구문분석,파싱) [C++ 소스]

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수식 파서트리.zip

"본문 내용"은 언제나 휴일 본 사이트에 있습니다.

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//Token.h

#pragma once

#include <iostream>

using namespace std;

#include <string.h>

 

class Token

{

    int priority;

public:

    virtual void View()const=0;

    bool MoreThanPriority(Token *token);   

protected:

    void SetPriority(int priority);

};

 

#include <vector>

using namespace std;

typedef vector<Token *> Tokens;

typedef Tokens::iterator TIter;

typedef Tokens::const_iterator CTIter; 

  

//Token.cpp

#include "Token.h"

 

bool Token::MoreThanPriority(Token *token)

{

    return priority>=token->priority;

}

 

void Token::SetPriority(int priority)

{

    this->priority = priority;

}

---

//Operator.h

#pragma once

#include "token.h"

 

class Operator :

    public Token

{

    char ch;

public:

    Operator(char ch);

    void View()const;

    int Calculate(int lvalue, int rvalue)const;

 

    static bool IsOperator(char ch);

    static bool IsOperator(const Token *token);

};

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//Operator.cpp

#include "Operator.h"

 

Operator::Operator(char ch)

{

    this->ch = ch;

    if((ch=='+')||(ch=='-'))

    {

        SetPriority(1);

    }

    else

    {

        SetPriority(2);

    }

}

 

void Operator::View()const

{

    cout<<ch<<" ";

}

int Operator::Calculate(int lvalue, int rvalue)const

{

    switch(ch)

    {

    case '+': return lvalue + rvalue;

    case '-': return lvalue - rvalue;

    case '*': return lvalue * rvalue;

    case '/':

        if(rvalue)

        {

            return lvalue / rvalue;

        }

        cout<<"divide zero error"<<endl;

        return 0;

    }

    throw "연산자 기호에 문제가 있습니다.";

}

 

bool Operator::IsOperator(char ch)

{

    return (ch=='+')||(ch=='-')||(ch=='*')||(ch=='/');

}

 

bool Operator::IsOperator(const Token *token)

{

    return dynamic_cast<const Operator *>(token)!=0;

}

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//Operand.h

#pragma once

#include "Token.h"

 

class Operand:

    public Token

{

    int value;

public:

    Operand(int value);

    void View()const;

    int GetValue()const;

    static bool IsDigit(char ch);

    static int ConvertStrToInt(const char *str,int &index);

    static bool IsOperand(const Token *token);   

};

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//Operand.cpp

#include "Operand.h"

 

Operand::Operand(int value)

{

    this->value = value;

    SetPriority(3);

}

 

void Operand::View()const

{

    cout<<value<<" ";

}

 

int Operand::GetValue()const

{

    return value;

}

 

bool Operand::IsDigit(char ch)

{

    return (ch>='0')&&(ch<='9');

}

int Operand::ConvertStrToInt(const char *str,int &index)

{

    int value = 0;

 

    while(IsDigit(str[index]))

    {

        value = value * 10 + str[index] - '0';

        index++;

    }

    return value;

}

 

bool Operand::IsOperand(const Token *token)

{

    return dynamic_cast<const Operand *>(token)!=0;

}

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//Lexer.h

#pragma once

#include "Operand.h"

#include "Operator.h"

 

class Lexer

{

    Tokens tokens;

public:

    bool MakeToken(const char *expr);

    Tokens GetTokens()const;   

    ~Lexer();

};

---

//Lexer.cpp

#include "Lexer.h"

 

bool Lexer::MakeToken(const char *expr)

{

    tokens.clear();

    int i = 0;

 

    while(expr[i])

    {

        if(Operator::IsOperator(expr[i]))

        {

            tokens.push_back(new Operator(expr[i]));

            i++;

        }

        else

        {

            if(Operand::IsDigit(expr[i]))

            {

                int value = Operand::ConvertStrToInt(expr,i);

                tokens.push_back(new Operand(value));

            }

            else

            {

                return false;

            }

        }

    }

    return true;

}

 

Tokens Lexer::GetTokens()const

{

    return tokens;

}

 

Lexer::~Lexer()

{

    TIter seek = tokens.begin();

    TIter last = tokens.end();

 

    for(  ;seek != last; ++seek)

    {

        delete (*seek);

    }

}

---

//SynAnalyzer.h

#pragma once

#include "Operator.h"

#include "Operand.h"

 

class SynAnalyzer

{

public:   

    static bool Analyze(Tokens tokens);

};

---

//SynAnalyzer.cpp

#include "SynAnalyzer.h"

 

bool SynAnalyzer::Analyze(Tokens tokens)

{

    int tcnt = tokens.size();

    if(tcnt%2==0)

    {

        return false;

    }

    if(Operand::IsOperand(tokens[0])==false)

    {

        return false;

    }

    for(int i = 1; i<tcnt; i+=2)

    {

        if(Operator::IsOperator(tokens[i])==false)

        {

            return false;

        }           

        if(Operand::IsOperand(tokens[i+1])==false)

        {

            return false;

        }

    }

    return true;

}

---

//Parser.h

#pragma once

#include "Operator.h"

#include "Operand.h"

class Parser

{

    Tokens tokens;

    struct Node

    {

        Token *token;

        Node *lc;

        Node *rc;

        Node(Token *token)

        {

            this->token = token;

            lc = rc = 0;

        }

    };

    Node *root;

public:

    Parser(Tokens tokens);

    ~Parser(void);

    void Parsing();

    void PostOrderView()const;

    int Calculate();

private:

    void Add(Token *token);

    void PostOrder(Node *sr)const;

    int PostOrderCalculate(Node *sr);

    void Clear(Node *sr);

};

---

//Parser.cpp

#include "Parser.h"

 

Parser::Parser(Tokens tokens)

{

    this->tokens = tokens;

}

 

Parser::~Parser(void)

{

    Clear(root);

}

 

void Parser::Clear(Node *sr)

{

    if(sr)

    {

        Clear(sr->lc);

        Clear(sr->rc);

        delete sr;

    }

}

 

void Parser::Parsing()

{

    int tcnt = tokens.size();

    root = new Node(tokens[0]);

    for(int i = 1; i<tcnt;i++)

    {

        Add(tokens[i]);

    }

}

 

void Parser::Add(Token *token)

{

    Node *now = new Node(token);

 

    Token *st = root->token;

    if(st->MoreThanPriority(token))

    {

        now->lc = root;

        root = now;

    }

    else

    {

       

        if(Operand::IsOperand(token)==false)

        {

            now->lc = root->rc;

            root->rc = now;

        }

        else

        {

            Node *pa = root;

            while(pa->rc)

            {

                pa = pa->rc;

            }

            pa->rc = now;

        }

    }

}

 

void Parser::PostOrderView()const

{

    PostOrder(root);

    cout<<endl;

}

 

void Parser::PostOrder(Node *sr)const

{

    if(sr)

    {

        PostOrder(sr->lc);

        PostOrder(sr->rc);

        sr->token->View();

    }

}

 

int Parser::Calculate()

{

    return PostOrderCalculate(root);

} 

 

int Parser::PostOrderCalculate(Node *sr)

{

    if(sr->lc)

    {

        int lvalue = PostOrderCalculate(sr->lc);

        int rvalue = PostOrderCalculate(sr->rc);

        Operator *op = dynamic_cast<Operator *>(sr->token);

        return op->Calculate(lvalue, rvalue);

    }

    else

    {

        Operand *op = dynamic_cast<Operand *>(sr->token);

        return op->GetValue();

    }

}

---

//Calculator.h

#pragma once

#include "Lexer.h"

#include "SynAnalyzer.h"

#include "Parser.h"

class Calculator

{

    char *expr;

    Tokens tokens;

public:

    Calculator(const char *expr);

    ~Calculator(void);

    void Run();

};

 

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//Calculator.cpp

#include "Calculator.h"

Calculator::Calculator(const char *expr)

{

    int len_p1 = strlen(expr)+1;

    this->expr = new char[len_p1];

    strcpy_s(this->expr,len_p1,expr);

}

Calculator::~Calculator(void)

{

    delete[] expr;

}

void Calculator::Run()

{

    cout<<expr<<"을 계산합니다. ..."<<endl;

    Lexer lexer;

    if(lexer.MakeToken(expr))

    {

        tokens = lexer.GetTokens();

        if(SynAnalyzer::Analyze(tokens))

        {

            Parser parser(tokens);

            parser.Parsing();

            parser.PostOrderView();

            cout<<expr<<"="<<parser.Calculate()<<endl;

        }

        else

        {

            cout<<"수식에 사용한 표현이 문법에 맞지 않습니다."<<endl;

        }

    }

    else

    {

        cout<<"사용할 수 없는 기호가 있습니다."<<endl;

    }

    cout<<endl;

}

---

//Program.cpp

#include "Calculator.h"

int main()

{

    char *tc_exprs[6]=

    {

        "2+3-5*5+6/2", "23*5/2+4*6", "2+4*5#6",

        "2+3*5+", "3+36+-7", "45+3*5-2+5/2*7"

    };

    for(int i = 0; i<6; i++)

    {

        Calculator *cal  = new Calculator(tc_exprs[i]);

        cal->Run();

        delete cal;

    }

    return 0;

}

 

▷ 실행 결과

2+3-5*5+6/2을 계산합니다. ...

2 3 + 5 5 * - 6 2 / +

2+3-5*5+6/2=-17

 

23*5/2+4*6을 계산합니다. ...

23 5 * 2 / 4 6 * +

23*5/2+4*6=81

 

2+4*5#6을 계산합니다. ...

사용할 수 없는 기호가 있습니다.

 

2+3*5+을 계산합니다. ...

수식에 사용한 표현이 문법에 맞지 않습니다.

 

3+36+-7을 계산합니다. ...

수식에 사용한 표현이 문법에 맞지 않습니다.

 

45+3*5-2+5/2*7을 계산합니다. ...

45 3 5 * + 2 - 5 2 / 7 * +

45+3*5-2+5/2*7=72

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