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a simple LL(1) parser code

Erik (1)
I'm not too familiar with forums, so I'm not sure if I posted this in the right topic. I apologize in advance if I'm on the wrong topic, or if I'm not allowed questions like this.

Ok now, this is a long shot, but I figured I would try asking for help anyhow.

I'm currently studying the topic syntax analyzer, focusing on LL(1) parsers. I understand the theories, how it works, etc. Recently, I was given a small task of creating an LL(1) parser. But to be honest, I am very weak in coding. So I asked help from a friend and he gave me this code.

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#include<iostream.h>
#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#include<string.h>


int main()
     {
       char tmp[15];
       char str[15], csf[15]={"E"};
       int ssm=0, i, j, v, k, pos=0, a;
       clrscr();

       char pt[6][5][4]={"" , "i" , "+" , "*" , "/",
             "E", "TX", "n" , "n" , "n",
             "X", "n" , "TX", "n" , "" ,
             "T", "VY", "n" , "n" , "n",
             "Y", "n" , ""  , "VY", "" ,
             "V", "i" , "n" , "n" , "n"};
     cout<<"\n Enter An Expression: "<<endl;
     cin>>str;

     while(str[ssm]!='/')
    {
      pos=0;
      while(csf[pos]!='E' &&
        csf[pos]!='X' &&
        csf[pos]!='T' &&
        csf[pos]!='Y' &&
        csf[pos]!='V' && csf[pos]!='\0')
        pos++;
    if (csf[pos]=='\0')
       break;

    for(i=1; i<6; i++)
      {
        if(csf[pos]==pt[i][0][0])
           break;
      }
       for(j=1; j<5; j++)
      {
         if(str[ssm]==pt[0][j][0])
        break;
      }
       if(strcmp(pt[i][j], "n")==0)
       {
          cout<<"\n Null Value: "<<endl;
          cout<<pt[i][j];
          exit;
       }

       for(k=0; k<pos; k++)
       tmp[k]=csf[k];
       tmp[k]='\0';
       strcat(tmp, pt[i][j]);

       int l= strlen(tmp);
       k=l;

       for(a=pos+1; csf[a]!='\0'; a++, k++)
       tmp[k]=csf[a];
       strcpy(csf, tmp);
    }


       strcat(csf, "/");
     if(strcmp(csf, str)==0)
         {
         cout<<"\t csf"<<csf;

         cout<<"\tstr"<<str;

         cout<<"\n Valid Expression: "<<endl;


         }

     else
         {
          cout<<"\n Invalid Expression:"<<endl;

         }


      getch();
      return 0;
}


To explain, I was working on this code the past week with a smart friend. It's in c++ and I'm using Code::Blocks. He refused to explain everything to me line by line, and he often wrote things for me rather than teaching them. I am not trolling nor asking you to do my project for me. I will be honest when I say i am very weak at writing codes. I am asking for help on explanations, and possibly ideas/solutions.
For those who have the time and want to help a total code-illiterate person, could you explain each line of code and basically what it does? What the certain words/numbers do?
(yes, I will admit I did not create this code entirely, or nearly at all. I have mentioned that)
Last edited on
Catfish (666)
http://en.wikibooks.org/wiki/C%2B%2B_Programming

This forum is best used for when you have problems. If you come with nothing, you leave with nothing.
toexii (79)
It isn't really reasonable to expect anyone to explain a piece of code entirely, line to line, if all the information you need is freely available on the internet and in books.

http://www.cplusplus.com/doc/tutorial/

That's one place out of many you can go.
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