编译原理算符优先矩阵的构造
算符优先法中算符优先矩阵的构造需要求出firstTerm以及lastTerm，由于这个是在预测分析法上进行修改的，结构体的定义并未进行修改，其中包含该非终结符a以及其对应的first（即为firstTerm）和follow（即为lastTerm），输入格式如下（以#结束输入）
Z::=E
E::=T|E+T
T::=F|T*F
F::=(E)|i
#
#includestd::vector<string> strN;
cin>>grammer;//输入规则
strN.push_back(grammer);
char str[10][80];
const char *ch = "|";
char *result;
vector<string> strN1; //存处理过“|”规则的
for(int i=0;i0][i]=grammer[i];
}
for(int h=grammer.length();h<80;h++)
{
str[0][h]=NULL;
}
result = strtok(str[0],ch);
while(result!=NULL)
{
strN1.push_back(result);
result = strtok(NULL,ch);
}
for(int i=1;grammer!="#";i++)
{
cin>>grammer;
strN.push_back(grammer);
/*处理转换的规则形式输入部分*/
for(int h=0;hfor(int h=grammer.length();h<80;h++)
{
str[i][h]=NULL;
}
result = strtok(str[i],ch);
while(result!=NULL)
{
strN1.push_back(result);
result = strtok(NULL,ch);
}
}
/*
获取firstTerm集合
*/
//直接获取firstTerm
for(unsigned i=0;i0];
gram[i].first="";
if(!Norterminal(strN[i][4]))
{
gram[i].first=strN[i][4];
}
else
{
if(!Norterminal(strN[i][5]))
{
gram[i].first=strN[i][5];
}
}
for(unsigned k=5;kif(strN[i][k]=='|')
{
if(!Norterminal(strN[i][k+1]))
{
gram[i].first+=strN[i][k+1];
}
else
{
if(!Norterminal(strN[i][k+2]))
{
gram[i].first+=strN[i][k+2];
}
}
}
}
}
int num=strN1.size();
//当第一个字符是非终结符时
for(int i=num-1;i>=0;i--)
{
for(unsigned l=0;l1;l++)
{
if(gram[l].a[0]==strN1[i][0])
{
for(unsigned h=0;h1;h++)
{
if(strN1[i][4]==gram[h].a[0]&&strN1[i][4]!=strN1[i][0])
{
gram[l].first+=gram[h].first;
string ustr(gram[l].first);
sort(ustr.begin(), ustr.end());
ustr.erase(unique(ustr.begin(), ustr.end()), ustr.end() );
gram[l].first=ustr;
break;
}
}
}
}
}
cout<<"firstTerm集合为："<for(unsigned i=0;i1;i++)
{
for(int k=0;kif(gram[i].first[k]==NULL)
{
gram[i].first.erase(gram[i].first.begin()+k);
}
}
cout<" "<string term="";
cout<<"终结符为："<for(unsigned i=0;i1;i++)
{
for(int j=0;jif(!Norterminal(strN[i][j])&&strN[i][j]!='$')
term+=strN[i][j];
}
string ustr(term);
sort(ustr.begin(), ustr.end());
ustr.erase(unique(ustr.begin(), ustr.end()), ustr.end() );
term=ustr;
}
cout</*转换规则形式*/
cout<<"转换后的规则形式为："<int listnumber =0;
for(unsigned i=0;i1&&i-1>=0;i++)
{
if(strN1[i].find("::")==-1)
{
string add="";
add=add+strN1[i-1][0]+"::="+strN1[i];
strN1[i]=add;
}
cout</*获取lastTerm*/
//直接获取lastTerm
for(int i=0;i1;i++)
{
for(unsigned l=0;l1;l++)
{
if(gram[l].a[0]==strN1[i][0])
{
for(unsigned h=0;h1;h++)
{
int k=strN1[i].length();
if(!Norterminal(strN1[i][k-1]))
{
gram[l].follow+=strN1[i][k-1];
string ustr(gram[l].follow);
sort(ustr.begin(), ustr.end());
ustr.erase(unique(ustr.begin(), ustr.end()), ustr.end() );
gram[l].follow=ustr;
break;
}
else
{
if(!Norterminal(strN1[i][k-2]))
{
gram[l].follow+=strN1[i][k-2];
string ustr(gram[l].follow);
sort(ustr.begin(), ustr.end());
ustr.erase(unique(ustr.begin(), ustr.end()), ustr.end() );
gram[l].follow=ustr;
break;
}
}
}
}
}
}
for(int i=num-1;i>=0;i--)
{
for(unsigned l=0;l1;l++)
{
if(gram[l].a[0]==strN1[i][0])
{
for(unsigned h=0;h1;h++)
{
int k=strN1[i].length();
if(Norterminal(strN1[i][k-1]))
{
for(unsigned h1=0;h11;h1++)
if(gram[h1].a[0]==strN1[i][k-1])
{
gram[l].follow+=gram[h1].follow;
string ustr(gram[l].follow);
sort(ustr.begin(), ustr.end());
ustr.erase(unique(ustr.begin(), ustr.end()), ustr.end() );
gram[l].follow=ustr;
break;
}
}
}
}
}
}
cout<<"lastTerm集合为："<for(unsigned i=0;i1;i++)
{
cout<" "<int list[term.length()][term.length()];
for(int i=0;ifor(int j=0;jlist[i][j]=0;
}
}
cout<<"相等的关系为："<for(int i=num-1;i>=0;i--)
{
for(int k=0;k1if(Norterminal(strN1[i][k]))
{
if(!Norterminal(strN1[i][k-1])&&!Norterminal(strN1[i][k+1]))
{
cout<1]<1]<for(int h=0;hif(strN1[i][k-1]==term[h])
for(int g=0;gif(strN1[i][k+1]==term[g])
{
list[h][g]=1;
}
}
}
}
}
else
{
if(!Norterminal(strN1[i][k+1]))
{
cout<1]<for(int h=0;hif(strN1[i][k]==term[h])
for(int g=0;gif(strN1[i][k+1]==term[g])
{
list[h][g]=1;
}
}
}
}
}
}
}
//cout<<"小于关系为："<
for(int i=0;i1 ;i++)
{
for(int k=0;kif(!Norterminal(strN1[i][k]))
{
if(Norterminal(strN1[i][k+1]))
{
for(int h=0;hif(strN1[i][k]==term[h])
{
for(int j=0;j1;j++)
{
if(strN1[i][k+1]==gram[j].a[0])
{
for(int g=0;gfor(int f=0;fif(gram[j].first[f]==term[g])
{
list[h][g]=2;
}
}
}
}
}
}
}
}
}
}
//大于关系
for(int i=0;i1;i++)
{
for(int k=0;kif(Norterminal(strN1[i][k]))
{
if(!Norterminal(strN1[i][k+1]))
{
for(int h=0;hif(strN1[i][k+1]==term[h])
for(int j=0;j1;j++)
{
if(strN1[i][k]==gram[j].a[0])
{
for(int g=0;gfor(int f=0;fif(gram[j].follow[f]==term[g])
{
list[g][h]=3;
}
}
}
}
}
}
}
}
}
for(int i=0;ifor(int j=0;jcout<<list[i][j]<<" ";
}
cout<cout<<"算符优先矩阵为："<cout<<" |";
for(int i=0;icout<10)<cout<<"|";
}
cout<cout<<"____________________________________________________________________________"<for(int i=0;iprintf("%2c",term[i]);
cout<<" "<<"|";
for(int j=0;jif(list[i][j]==0)
cout<10)<<" "<<"|";
if(list[i][j]==1)
cout<10)<<"="<<"|";
if(list[i][j]==2)
cout<10)<<"<"<<"|";
if(list[i][j]==3)
cout<10)<<">"<<"|";
}
cout<cout<<"____________________________________________________________________________"< 运行结果如下：
