简单的词法分析程序

编译原理实验：简单的词法分析程序

#include<iostream>
#include<fstream>
#include<string>
using namespace std;
#define D 10
#define  O 11
#define  K 17

char Delimiter[D]={'<', '>', ',', ';', '(', ')', '{', '}' ,'[',']' };
char  Operator[O]={'=','+',  '-', '*', '/', '%'};   //">=", "<=", "<<",">>" "++", "--","=="
string keyword[K]={"include",  "define", "iostream", "using", "namespace", "std", "int", "main","double", "bool", "float", "cout", "for", "else", "while", "do","cin"};

//判断是不是界符
bool Delimit(const char c)
{
    for(int i=0;i<D ;i++)
    {
        if(c==Delimiter[i])
            return true;
    }
    return false;
}

//判断是不是运算符
bool Operat(const char c)
{
    for(int i=0;i<O;i++)
    {
        if(c==Operator[i])
            return true;
    }
    return false;
}

//判断是不是关键字
bool Keyword(string s)
{
   for(int i=0;i<K;i++)
   {
       if(s==keyword[i])
           return true;
   }
   return false;
}

//判断是不是字母
bool Character(const char c)
{
    if((c>='a'&&c<='z')||(c>='A'&&c<='Z'))
        return true;
    else 
        return false;
}
//判断是不是数字
bool Number(const char c)
{
    if(c>='0'&&c<='9')
        return true;
    else 
        return false;
}

//判断string中是否为数字,包括小数、科学计数法
bool Strnumber(string s)
{
    for(string::iterator itr=s.begin();itr!=s.end();itr++ )
    {
        if(Number(*itr))
            continue;
        else if (*itr=='.')
                for(string::iterator it=itr+1;it!=s.end();it++ )
                    if (Number(*it)==true)
                        break;
                    else if(*it=='e')
                    {
                        for(string::iterator itr1=it+1;itr1!=s.end();itr1++)
                        {
                            if (!Number(*itr1))
                            {
                                return false;
                            }
                        }
                    }
                    else
                        return false;
        else if (*itr=='e')
            {
                for(string::iterator itr1=itr+1;itr1!=s.end();itr1++)
                {
                    if (!Number(*itr1))
                    {
                        return false;
                    }
                }
            }
        else
        {
            return false;
        }
        }
    return true;
}



//判断是否为空格
bool Kongge(char c)
{
    if (c==' ' ||c=='\n' ||c=='\t')
        return true;
    else 
        return false;
}


int main()
{    
    ifstream sin("daima.txt");
    ofstream sout("shuchu.txt");
    if(!sin.is_open())
        cout<<"文件打开出错"<<endl;
    char c;
    c=sin.get();
    while(!sin.eof())
    {
        if(Delimit(c))
        {
            string s;
            if (c=='>')
            {
                s.push_back(c);
                sin.get(c);
                if (c=='='||c=='>')
                {
                    s.push_back(c);
                    sout<<s<<'\t'<<"Operator"<<endl;
                    sin.get(c);
                } 
                else
                    sout<<s<<'\t'<<"Delimiter"<<endl;
            } 
            else if (c=='<')
            {
                s.push_back(c);
                sin.get(c);
                if (c=='='||c=='<')
                {
                    s.push_back(c);
                    sout<<s<<'\t'<<"Operator"<<endl;
                    sin.get(c);
                } 
                else
                    sout<<s<<'\t'<<"Delimiter"<<endl;
            } 
            else
            {
                sout<<c<<'\t'<<"Delimiter"<<endl;
                c=sin.get();
            }
        }
        else if(Operat(c))
        {
            if (c=='=')
            {
                string s;
                s.push_back(c);
                c=sin.get();
                if (c=='=')
                {
                    s.push_back(c);
                    sout<<s<<'\t'<<"Operator"<<endl;
                    sin.get(c);
                } 
                else
                {
                    sout<<s<<'\t'<<"Operator"<<endl;
                }
            } 
            else if(c=='+')
            {
                string s;
                s.push_back(c);
                c=sin.get();
                if (c=='+')
                {
                    s.push_back(c);
                    sout<<s<<'\t'<<"Operator"<<endl;
                    sin.get(c);
                } 
                else
                {
                    sout<<s<<'\t'<<"Operator"<<endl;
                }
            }
            else if(c=='-')
            {
                string s;
                s.push_back(c);
                c=sin.get();
                if (c=='-')
                {
                    s.push_back(c);
                    sout<<s<<'\t'<<"Operator"<<endl;
                    sin.get(c);
                } 
                else
                {
                    sout<<s<<'\t'<<"Operator"<<endl;
                }
            }
        }
        else if(c=='_')
        {
            string s;
            while(true)
            {
                if(Kongge(c)==true||Operat(c)==true ||Delimit(c)==true)
                    break;
                else
                {
                    s.push_back(c);
                    sin.get(c); 
                }
            }
            sout<<s<<'\t'<<"Identifier"<<endl;
        }
        else if(Number(c))
        {
            string s;
            while(true)
            {
                if(Kongge(c)==true||Operat(c)==true ||Delimit(c)==true)
                    break;
                else
                {
                    s.push_back(c);
                    sin.get(c);  
                }
            }
            if(Strnumber(s)==true)
                sout<<s<<'\t'<<"Number"<<endl;
            else
                sout<<s<<'\t'<<"error character"<<endl;
        }
        else if(Character(c))
        {
            string s;
            while(true)
            {
                if(Kongge(c)==true||Operat(c)==true ||Delimit(c)==true)
                    break;
                else
                {
                    s.push_back(c);
                    sin.get(c);    
                }
            }
            if(Keyword(s))
                sout<<s<<'\t'<<"Keyword"<<endl;
            else
                sout<<s<<'\t'<<"Identifier"<<endl;
        }
        else if (Kongge(c)==false)
        {
            sout<<c<<'\t'<<"Error Character"<<endl;
            c=sin.get();
        }
        else
            c=sin.get();
    }
    cout<<"词法分析结束"<<endl;
    
    /**sin.get(c);
    cout<<c<<endl;
    string read;
    while(getline(sin, read, ' ')) // 逐词读取方法三
     {
         cout << read << endl;
     }
    sout.write(c,strlen(c));
    **/
    sin.close();
    sout.close();
    return 0;
}