【文件属性】：
文件名称：编译原理 词法分析器的模拟
文件大小：3KB
文件格式：CPP
更新时间：2012-06-08 05:56:37
词法分析器
#include
#include
using namespace std;
#define MAX 22
char ch =' ';
string key[15]={"begin","end","if","then","else","while","write","read",
"do", "call","const","char","until","procedure","repeat"};
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){
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*********************"<
