自顶向下的语法分析：递归下降法.doc

实验二：自顶向下的语法分析：递归下降法
1、实验目的：编制一个递归下降分析程序，实现对词法分析程序所提供的单词序列的语法检查和结构分析。
2、实验要求：
文法（教材199页）
（1）把词法分析作为语法分析的子程序实现（5分）
（2）独立的语法分析程序（4分）
（3）输入串以‘#’结束，输出成功（success）或出错（error）、指出出错位置（行、列以及错误类型）

#include<iostream>
#include<fstream>
#include<string>
#include<stdlib.h>
#defineMAX1024
usingnamespacestd;

stringDataType[]={"int","bool","char","void"};
stringKeyWords[]={"if","else","do","while","for","break","in","continue","goto",
"switch","case","default","foreach","try","catch","finally","throw","return"};
stringOperator[]={"+","-","*","/","%","&&","||",">","<",">=","<=","==","!=","^","&","|",
"~","<<",">>","=","+=","-=","*=","/=","%=","&=","|=","^=","<<=",">>="};
charSeperator[]={'','.','(',')','[',']',';','{','}',',','?',':'};

structIdentity
{
stringvalue;
inttype;
};

ifstreaminFile("D:\\output.txt");
introw=1;

IdentityID[10000];
intnWord=0;

voidExpression()
{
stringword;
intsyn;
inFile>>word>>syn;
if(syn==71)
{
stringtmp1;
inttmp2;
inFile>>tmp1>>tmp2;
if(tmp2!=199)
{
if(tmp2>=30&&tmp2<71)
{
inFile>>tmp1>>tmp2;
if(tmp2==71)
{
inFile>>tmp1>>tmp2;
if(tmp2!=199)
cout<<"erroroccursinrow"<<row<<",miss\";\"!"<<endl;
}
else
cout<<"erroroccursinrow"<<row<<",missidentity!"<<endl;
}
else
cout<<"erroroccursinrow"<<row<<",missoperator!"<<endl;
}
}
}

intlook(stringvalue)
{
inti;
for(i=0;i<nWord;i++)
if(ID[i].value==value)
returni;
return-1;
}

voidGrammerAnalyse()
{
stringword;
intsyn;
inti;
while(!inFile.eof())
{
i=0;
inFile>>word>>syn;
if(word=="#")
row++;
else
{
if(syn>0&&syn<10)
{
stringtmp1;
inttmp2;
inFile>>tmp1>>tmp2;
if(tmp2==71)
{
intindex=look(tmp1);
//ID[index].type=syn;
inFile>>tmp1>>tmp2;
if(tmp2!=199)
{
if(tmp1=="=")
{
Expression();
}
else
cout<<"erroroccursinrow"<<row<<",miss\";\"!"<<endl;
}
}
else
cout<<"erroroccursinrow"<<row<<",missidentity!"<<endl