编译原理预测分析程序

直接上代码：

#include<cstdio>
#include<iostream>
#include<map>
#include<vector>
#include<string>
#include<set>
#include<stack>
#include<algorithm>
#include<Windows.h>
using namespace std;

vector<char>VN;
vector<char>VT;
bool vis_VN[30];
bool vis_VT[300];
bool LL_flag=true;
void init_visit()
{
    for(int i=0;i<26;i++)
        vis_VN[i]=true;
    for(int i=0;i<300;i++)
        vis_VT[i]=true;   
}

map<char,vector<string> >mp;//用来存文法 
map<char,set<char> >first;//用来存first集 
map<char,set<char> >follow;//用来存follow集 
map<char,map<char,set<string> > >pretable;//预测分析表 

bool is_VN(char x)//判断是否是非终结符 
{
    if(x>='A'&&x<='Z')
        return true;
    else
        return false;
}

void fun_table(char A,string str)//预测分析表的构建 
{
    set<char>ans;
    bool tbool=false;
    for(int i=0;i<str.size();i++)
    {
        char ch=str[i];
        if( !( is_VN(ch) ) )//以终结符开头 
        {
            if(ch !='0')
            {
                ans.insert(ch);
                tbool=true;
            }
               break;
        }
        else
        {
               set<char>::iterator it;
               for (it = first[ch].begin(); it != first[ch].end(); it++){
                   if(*it!='0')
                       ans.insert(*it);
               }
               tbool=true;      
               for(int j=0;j<mp[ch].size();j++)
               {
                   if(mp[ch][j]=="0")
                       tbool=false;
               }
               if(tbool) break;
        }
    }
    if(!tbool)
    {
        set<char>::iterator it;
        for (it = follow[A].begin(); it != follow[A].end(); it++){
               if(*it!='0')
                   ans.insert(*it);
        }
    }
    set<char>::iterator it;
    for (it = ans.begin(); it != ans.end(); it++){
        pretable[A][*it].insert(str);
    }    
} 

void fun_first(char A)//处理A的first集 
{
    string flag="";
    bool empty_flag=true;
    for(int i=0;i<mp[A].size();i++)
    {
        flag=mp[A][i];
        for(int flagi=0;flagi<flag.size();flagi++)
        {
            char ch=flag[flagi];    
            if( !( is_VN(ch) ) )//以终结符开头 
            {
                first[A].insert(ch);
                empty_flag=false;
                break;
            }
            else
            {
                fun_first(ch);
                set<char>::iterator it;
                for (it = first[ch].begin(); it != first[ch].end(); it++){
                    if(*it!='0')
                        first[A].insert(*it);
                }
                bool tbool=true;
                for(int j=0;j<mp[ch].size();j++)
                {
                    if(mp[ch][j]=="0")
                        tbool=false;
                }
                if(tbool)
                {
                    empty_flag=false;
                    break;
                 } 
            }
        }
        if(empty_flag)
            first[A].insert('0');        
    }
}

void fun_follow(char A)//处理A的follow集
{
    for(int i=0;i<VN.size();i++)
    {
        char ch=VN[i];
        for(int j=0;j<mp[ch].size();j++)
        {
            string s=mp[ch][j];
            int k=0;
            for(k=0;k<s.length();k++)
            {
                if(s[k]==A)
                {
                    if(k==s.length()-1)//如果A可直接或间接位于ch推导式的末位 ,将ch的follow集加入到A的follow集 
                    {
                        set<char>::iterator it;
                        for (it = follow[ch].begin(); it != follow[ch].end(); it++)
                        {
                            follow[A].insert(*it);
                        }
                    }
                    else
                    {
                        if(is_VN(s[k+1]))//A的下一位是非终结符 
                        {
                            bool flag2=false;
                            set<char>::iterator it;
                            for (it = first[s[k+1]].begin(); it != first[s[k+1]].end(); it++){
                                if(*it!='0')
                                    follow[A].insert(*it);//将A下一位非终结符的first加入A的follow集 (除去0) 
                            }
                            for(int t=0;t<mp[s[k+1]].size();t++)
                            {
                                if(mp[s[k+1]][t]=="0")
                                    flag2=true;
                            } 
                            if(flag2)//A下一位非终结符可推倒出0 
                                s[k+1]=A;
                        }
                        else
                        {
                            follow[A].insert(s[k+1]);
                        }
                    }
                }
            }
        }    
    } 
}
 
void show_first_follow()//显示first集和follow集 
{
    cout<<"First集如下:"<<endl; 
    for(int i=0;i<VN.size();i++)
    {
        fun_first(VN[i]);       
        cout<<VN[i]<<": ";
        char tch=VN[i];
        set<char>::iterator it;
        for (it = first[tch].begin(); it != first[tch].end(); it++){
                cout<<*it<<" ";
        }
        cout<<endl;
    } 
    cout<<"Follow集如下:"<<endl; 
    follow[VN[0]].insert('#');
    for(int i=0;i<VN.size();i++)
        fun_follow(VN[i]);
    for(int i=0;i<VN.size();i++)
    {
        fun_follow(VN[i]);
        
        cout<<VN[i]<<": ";
        char tch=VN[i];
        set<char>::iterator it;
        for (it = follow[tch].begin(); it != follow[tch].end(); it++){
                cout<<*it<<" ";
        }
        cout<<endl;
    } 
}

void show_pretable()//显示预测分析表 
{
    cout<<"预测分析表如下:"<<endl;
    int x=VN.size()+1,y=VT.size()+1;
    int spaceflag=0;
    for(int i=1;i<=2*x+1;i++)
    {
        for(int j=1;j<=12*y+1;j++)
        {
            if(i%2==1)
                cout<<'-';
            else
            {    
                if(i==2&&j%12==7&&j>12)
                    cout<<VT[j/12-1]; 
                else
                {
                    if(j%12==1)
                        cout<<'|';
                    else if(j==7&&i>2)
                        cout<<VN[i/2-2];
                    else
                    {
                        if(i>3&&j>13)
                        {
                            if(j%12==3)
                            {
                                int m=i/2-2,n=j/12-1;
                                set<string>::iterator it;
                                if(!pretable[VN[m]][VT[n]].empty())
                                {
                                    spaceflag-=pretable[VN[m]][VT[n]].size()-1;
                                    if(pretable[VN[m]][VT[n]].size()>1)
                                        LL_flag=false;
                                }
                                for (it = pretable[VN[m]][VT[n]].begin(); it != pretable[VN[m]][VT[n]].end(); it++){
                                           cout<<*it<<" ";
                                           spaceflag-=(*it).size();
                                   }
                                   if(spaceflag==0)
                                    cout<<' ';
                                    
                            }
                            else
                            {
                                if(spaceflag==0)
                                    cout<<' ';
                                else
                                    spaceflag++;
                            }    
                        }
                        else
                            cout<<' ';
                        
                    }
                }
                
            }
        }
        cout<<endl;
    }
         
} 

string stackstr,teststr; 
void controlling()//总控程序+过程显示+错误处理 
{
    cout<<"Please input a string:"<<endl;
    string checkstr;    
    stack<char>checkstack;
    checkstack.push('#');
    checkstack.push(VN[0]);
    stackstr="#";
    stackstr+=VN[0];
    getchar();
    cin>>checkstr;
    checkstr+='#';
    teststr=checkstr;
    bool strflag=true;
    int where;
    for(int i=0;i<checkstr.size();i++)
    {
        if(checkstack.top()!='0')
        {
            cout<<stackstr;
                for(int j=1;j<=20-stackstr.length();j++)
                    cout<<" ";
            cout<<checkstr[i]<<"          ";
            for(int j=i+1;j<checkstr.size();j++)
                cout<<checkstr[j];
            cout<<endl;
        }
        
         
        if(checkstack.empty())
        {
            strflag=false;
            where=i;
            break;
        }        
        char ch1=checkstack.top(),ch2=checkstr[i];
        checkstack.pop();
        if(ch1=='0')
        {
            i--;
            continue;
        }
        if(!is_VN(ch1))
        {
            if(ch1!=ch2)
            {
                strflag=false;
                where=i;
                break;
            }
            stackstr.erase(stackstr.end()-1,stackstr.end()) ;       
        }
        else
        {
            if(pretable[ch1][ch2].empty())
            {
                strflag=false;
                where=i;
                break;
            }
            else
            {
                stackstr.erase(stackstr.end()-1,stackstr.end()) ;  
                set<string>::iterator it;
                it=pretable[ch1][ch2].begin();
                string s=*it;
                for(int j=s.length()-1;j>=0;j--)
                {
                    checkstack.push(s[j]);
                    if(s[j]!='0')
                        stackstr+=s[j]; 
                }
                i--;
            }
        }
    }
    if(strflag)
        cout<<"ok";
    else
    {
        cout<<"error near column "<<where+1<<endl;
        for(int i=0;i<checkstr.length()-1;i++)
        {
            if(i==where)
            {
                HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);  
                WORD wOldColorAttrs;  
                CONSOLE_SCREEN_BUFFER_INFO csbiInfo;  
  
                // Save the current color  
                GetConsoleScreenBufferInfo(h, &csbiInfo);  
                wOldColorAttrs = csbiInfo.wAttributes;  
  
                // Set the new color  
                SetConsoleTextAttribute(h, FOREGROUND_RED | FOREGROUND_INTENSITY | BACKGROUND_GREEN);
                cout<<checkstr[i];
                SetConsoleTextAttribute(h, wOldColorAttrs);
                continue;
            
            }
            cout<<checkstr[i];
        }
        if(where==checkstr.length()-1)
        {
            HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);  
            WORD wOldColorAttrs;  
            CONSOLE_SCREEN_BUFFER_INFO csbiInfo;  
  
            // Save the current color  
            GetConsoleScreenBufferInfo(h, &csbiInfo);  
            wOldColorAttrs = csbiInfo.wAttributes;  
  
            // Set the new color  
            SetConsoleTextAttribute(h, FOREGROUND_RED | FOREGROUND_INTENSITY | BACKGROUND_GREEN);
            cout<<'?';
            SetConsoleTextAttribute(h, wOldColorAttrs);
        }
    }
}

int main()
{
    init_visit(); 
    int k=1;
    char vn;
    string str;
    while(cin>>vn&&vn!='#'&&cin>>str)
    {
        if(vis_VN[vn-'A']==true)//不重复存vn 
        {
            VN.push_back(vn);
            vis_VN[vn-'A']=false;
        }        
        mp[vn].push_back(str);//代表vn可以推导出str
        for(int i=0;i<str.size();i++)
        {
            if(!is_VN(str[i])&&vis_VT[(int)str[i]]==true&&str[i]!='0')
            {
                VT.push_back(str[i]);
                vis_VT[(int)str[i]]=false;
            }
        }
        
    }
    VT.push_back('#');
    sort(VT.begin(),VT.end()-1); 
    show_first_follow();
    for(int i=0;i<VN.size();i++)//构建预测分析表 
    {
        for(int j=0;j<mp[VN[i]].size();j++)
        {
            fun_table(VN[i],mp[VN[i]][j]);
        }
    }    
    show_pretable();
    if(LL_flag)
        cout<<"This is a LL(1)"<<endl;
    else
    {
        cout<<"This is not a LL(1)"<<endl;
        return 0;
    }
    while(1)
    {
        controlling(); 
        cout<<endl;
    }
       
        
}

 

样例：

E TA
A +E
A 0
T FB
B T
B 0
F PC
C *C
C 0
P (E)
P a
P b
P v
#

S Ab
A a
A b
A 0
#

S ABc
A a
A 0
B b
B 0
#