Math.cpp

#include "Math.h"
#include "Tree.h"

#define ADD_FUNC(func) \
    if (strcmp(f.c_str(), func) == 0)\
        {\
            tmp = new CNode(func, GetExp());\
        }\
        else\

Math::Math()
{
    str = string();
}

void Math::PutStr(string st)
{
    str = st;
    S = str.begin();
}

string Math::GetEquation()
{
    ifstream File;
    File.open ("exp.txt");
    if (File.is_open()) printf("File is open\n");
    getline(File, str);
    cout << str << endl;
    File.close();
    return str;
}

string Math::PrepareEquation()
{
    string tmp;
    int count = 0;
    try
    {
        for(S = str.begin(); S != str.end(); S++) 
        {
            if(((*S >= '0') && (*S <= '9')) || ((*S >= 'a') && (*S <= 'z')) || (*S == '+') || (*S == '-') || (*S == '*') || (*S == '/') || (*S == '^'))
            {
                tmp += *S;
            }
            else if ((*S == '(') || (*S == ')'))
            {
                tmp += *S;
                if (*S == '(') 
                {
                    count += 1;
                }
                if (*S == ')')
                { 
                    count -= 1;
                }
                if (count < 0) 
                {
                    break;
                }
            }
            else if(*S == '\0')
            {
                break;
            }
            else if((*S != ' ') && (*S != 10))
            {
                throw string("Incorrect expression. Please correct it\n") ;
            }
        }
        if(count != 0)
        {
            throw string("Incorrect expression. Check '(' and ')'. Please correct it\n") ;
        }
    }
    catch(string ex)
    {
        cout << ex << endl;
        exit(-1);
    }
    return tmp;
}


CNode* Math::GetExp()
{
    CNode* tmp = GetMulDiv();
    while(*S == '-' || *S =='+')
    {
        if (*S == '+') 
        {
            S++;
            CNode* tmp1 = new CNode('+', tmp, GetMulDiv());
            tmp = tmp1;
        }
        else if (*S == '-')
        {
            S++;
            CNode* tmp1 = new CNode('-', tmp, GetMulDiv());
            tmp = tmp1;
        }
    }
    return tmp;
}

CNode* Math::GetMulDiv()
{
    CNode* tmp= GetPow();
    while(*S == '*' || *S == '/')
    {
        if (*S == '*') 
        {
            S++;
            CNode* tmp1 = new CNode('*', tmp, GetPow());
            tmp = tmp1;
        }
        else if (*S == '/')
        {
            S++;
            CNode* tmp1 = new CNode('/', tmp, GetPow());
            tmp = tmp1;
        }
    }
    return tmp;
}

CNode* Math::GetPow()
{
    CNode* tmp = GetPas();
    if(*S == '^')
    {   
            S++;
            CNode* tmp1 = new CNode('^', tmp, GetPas());
            tmp = tmp1;
    }
    return tmp;
}

CNode*  Math::GetPas()
{
    CNode* tmp;
    if (*S == '(')
    {
        S++;
        tmp = GetExp();
        try
        {
            if (*S != ')')
                throw string ("Expected ')'. Please correct expression\n");
        }
        catch(string ex)
        {
            cout << ex << endl;
            exit(1);
        }
        S++;
    }
    else if (*S == 'x') //пока считаем, что переменная только x( потом добавить все переменные)
    {
        S++;
        tmp = new CNode('x');
    }
    else if (((*S >= 'a') && (*S <= 'z')))
    {
        tmp = GetFunc();
    }
    else
    {
        tmp = GetNum();
    }
    return tmp;
}

CNode* Math::GetFunc()
{
    CNode* tmp;
    string f;
    while(*S != '(')
    {
        f += *S;
        S++;
    }
    S++;
    try
    {
        ADD_FUNC("sin")
        ADD_FUNC("cos")
        ADD_FUNC("tg")
        ADD_FUNC("ctg")
        ADD_FUNC("arcsin")
        ADD_FUNC("arccos")
        ADD_FUNC("arctg")
        ADD_FUNC("arcctg")
        ADD_FUNC("ln")
        ADD_FUNC("lg")
        ADD_FUNC("sh")
        ADD_FUNC("ch")
        ADD_FUNC("th")
        ADD_FUNC("cth") 
        {
            throw string ("This function not exist. Please correct expression\n");
        }
        S++;
    }
    catch (string ex)
    {
        cout << ex << endl;
        exit(1);
    }
    return tmp;
}

CNode* Math::GetNum()
{
    double val = 0.0;
    string::iterator debug = S;
    while('0' <= *S && *S <= '9')
    {
        val = val*10 + *S - '0';
        S++;
    }
    try
    {
        if(debug == S)
            throw string("Expected number. Please correct expression\n");
    }
    catch(string ex)
    {
        cout << ex << endl;
        exit(1);
    }
    
    CNode* tmp = new CNode(val);
    return tmp;
}