token.cpp

一个命令行运算器源代码 用C++写的命令行运算器

#include "token.h"
#include <iostream>

int Token::varpri = LO;

Token::Token(char c):type(OP)
{
    content.sym = c;

    switch(c)
    {
        case '+':
        case '-':
            priority = varpri - 1;
            break;

        case '*':
        case '/':
            priority = varpri - 2;
            break;

        case '^':
            priority = varpri - 3;
            break;

        case '(':
            varpri -= 5;
            break;

        case ')':
            varpri += 5;
            break;

        case EOF:
            break;

        case '\0':  //identified the end of string
            if(varpri != LO)
            {
                std::cerr<<"Missing token!"<<std::endl;
                exit(1);
            }
            break;

        default:
            std::cerr<<"unkowned token!"<<std::endl;
            exit(1);
    }
}

Token::Token(double d):type(EX),priority(varpri - 4)
{
    content.num = d;
}

//bool Token::operator==(const Token& it)
//{
//    if(typ() != it.typ())
//        return false;
//    else if(typ() == EX)
//        return num() == it.num();
//
//    else
//        return sym() == it.sym();
//}

//bool Token::operator!=(const Token& it)
//{
//    return !(*this == it);
//}