/*
lee's 词法分析器
Builde 2004年12月8日
CUMT online.cumt.edu.cn
*/
#include<iostream.h>
#include<fstream.H>
#include<stdlib.h>
#include<string.h>
bool letter(char);
bool digit(char);
char keyword[9][9]={"main","for","if","else","while","do","for","int","char"};
char character; //字符变量，存放最新读进的源程序字符
char token[50]; //字符数组，存放构成单词符号的字符串
bool flags;
bool putchar()
{
cout<<"您是否是把代码文件写入了wh.txt文件中?[y(Y)/n(N)]..."<<endl;
char get1;
cin>>get1;
if(get1=='Y'||get1=='y')
{
return true;
}
else
{
return false;
}
}
//-----------------------
void getbc()
{
if(character==' '||character==char(10))
{
if(strlen(token)!=0)
{
for(int k=0;k<9;k++)
{
int a;
if(strlen(keyword[k])>strlen(token))
a=strlen(keyword[k]);
else
a=strlen(token);
if (!strncmp(keyword[k],token,a))
{
cout<<"< "<<token<<" , 关键字>"<<endl;
flags=false;
goto Loop;
}
}
if(!strncmp("+",token,1)||!strncmp("-",token,strlen(token)))
{
cout<<"< "<<token<<" , 算术运算符>"<<endl;
flags=false;
goto Loop;
}
else if(!strncmp("<",token,1)||!strncmp("<=",token,strlen(token))||!strncmp("=<",token,strlen(token))||!strncmp("<>",token,strlen(token))||!strncmp("=",token,strlen(token))||!strncmp(">=",token,strlen(token))||!strncmp(">",token,strlen(token)))
{
cout<<"< "<<token<<" , 关系运算符>"<<endl;
flags=false;
goto Loop;
}
else if(!strncmp(":=",token,2))
{
cout<<"< "<<token<<" , 赋值运算符>"<<endl;
flags=false;
goto Loop;
}
else if(!strncmp(":",token,strlen(token)))
{
cout<<"< "<<token<<" , 冒号>"<<endl;
flags=false;
goto Loop;
}
else if(!strncmp(";",token,strlen(token)))
{
cout<<"< "<<token<<" , 分号>"<<endl;
flags=false;
goto Loop;
}
else if (!strncmp(")",token,strlen(token)))
{
cout<<"< "<<token<<" , 右括号>"<<endl;
flags=false;
goto Loop;
}
else if (!strncmp("(",token,strlen(token)))
{
cout<<"< "<<token<<" , 左括号>"<<endl;
flags=false;
goto Loop;
}
else
{
if (flags==true)
{
cout<<"< "<<token<<", 数>"<<endl;
flags=false;
goto Loop;
}else
cout<<"< "<<token<<", 标示符>"<<endl;
flags=false;
goto Loop;
}
Loop: for(int j=strlen(token);j>=0;j--)
token[j]='\0';
}
}
else if(digit(character))
{
token[strlen(token)]=character;
if(strlen(token)==1)
{
flags=true;
}
}
else if(letter(character))
{
token[strlen(token)]=character;
}
else
token[strlen(token)]=character;
}
bool letter(char character1)
{
if(((char(97)<=character1)&&(character1<=char(122)))||((char(65)<=character1)&&(character1<=char(90))))
return true;
else
return false;
}
bool digit(char character1)
{
if((char(48)<=character1)&&(character1<=char(57)))
return true;
else
return false;
}
void main()
{
bool one;
one=putchar();
if(one==false)
{
cout<<"请准备好了代码再运行此文件"<<endl;
}
else
{
fstream infile;
infile.open ("wh.txt",ios::in);
char ch;
while(infile.get (ch))
{
character=ch;
getbc();
}
int tmp;
cin>>tmp;
}
}
