编译原理词法分析程序

#include 
#include
#include
#include
#include
using namespace std;
#define  MAX 22
char ch =' ';
string key[15]={"switch","break","if","then","else","while","write","read",
"do", "int","const","char","float","double","for"};

int Iskey(string c)    //关键字判断
{
   int i;
   for(i=0;i='a'))||((c<='Z')&&(c>='A')))
        return 1;
    else
        return 0;
}
int IsDigit(char c)    //判断是否为数字
{
     if(c>='0'&&c<='9')
        return 1;
     else
        return 0;
}
void analyse(FILE *fpin)  //词法分析程序
{
    string arr="";
    while((ch=fgetc(fpin))!=EOF)
    {
        arr="";
        if(ch==' '||ch=='\t'||ch=='\n')
        {
        }
        else if(IsLetter(ch))
        {
            while(IsLetter(ch)||IsDigit(ch))
            {
                if((ch<='Z')&&(ch>='A'))
                    ch=ch+32;
                arr=arr+ch;
                ch=fgetc(fpin);
            }
            fseek(fpin,-1L,SEEK_CUR);
            if (Iskey(arr))
            {
                cout<' :{ch=fgetc(fpin);
                         if(ch=='=') cout<<">="<<"\t$运算符"<')cout<<">>"<<"\t$输入控制符"<"<<"\t$运算符"<') cout<<"<>"<<"\t$运算符"<>in_fn;
       if((fpin=fopen(in_fn,"r"))!=NULL)
            break;
       else
        cout<<"文件路径错误！请输入源文件名（包括路径和后缀名）:";
    }
   cout<<"\n********************分析如下*********************"<