Logo 
Search:

C++ Programming Articles

Submit Article
Home » Articles » C++ Programming » ParsingRSS Feeds

PROGRAM TO IMPLEMENT RECURSIVE DESCENT PARSER

Posted By: Adalric Fischer     Category: C++ Programming     Views: 9723

PROGRAM TO IMPLEMENT RECURSIVE DESCENT PARSER.

Code for PROGRAM TO IMPLEMENT RECURSIVE DESCENT PARSER in C++ Programming

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


typedef struct treenode
{
    char info;
    treenode *left;
    treenode *right;
}node;


    node * proc_e(char input[],int &ssm);
    node * proc_t(char input[],int &ssm);
    node * proc_v(char input[],int &ssm);
    void traversal(node *temp);

void main()
{
    char input[20];
    int ssm=0;
    node *root;
//    clrscr();

    cout<<endl<<"ENTER THE STRING TO BE PARSED:";
    cin>>input;

    root = proc_e(input,ssm);
    cout<<endl<<"CONTENTS OF THE PARSE TREE:";
    traversal(root);


    getch();
}


void traversal(node *temp)
{


   if(temp != NULL)
   {
    traversal(temp->left);
    cout<<temp->info;
    traversal(temp->right);
    }
}


//PROCEDURE FOR NT E:

node * proc_e(char input[],int &ssm)
{
    node *a,*b;

    a=proc_t(input,ssm);

    while(input[ssm]=='+')
    {
        ssm++;
        b=proc_t(input,ssm);

        node *temp;
        temp=new node; //(node*)malloc(sizeof(node));
        temp->info='+';
        temp->left=a;
        temp->right=b;

        a=temp;

    }

    return a;
}





//PROCEDURE FOR NT T:

node * proc_t(char input[],int &ssm)
{
    node *a,*b;

    a=proc_v(input,ssm);
    ssm = ssm + 1;

    while(input[ssm] == '*')
    {
        ssm++;

        b=proc_v(input,ssm);
        node *temp;

        temp=new node;//(node *)malloc(sizeof(node));
        temp->info='*';
        temp->left=a;
        temp->right=b;

        a=temp;
        ssm = ssm +1;
    }

    return a;


}



//PROCEDURE FOR NT V:

node * proc_v(char input[],int &ssm)
{
    node *a;

    if(input[ssm]=='I')
    {
        node *temp;
        temp=new node; //(node*)malloc(sizeof(node));
        temp->info='I';
        temp->left=NULL;
        temp->right=NULL;
        return temp;
    }
    else
    {
        cout<<endl<<"ERROR. INVALID SYMBOL "<<input[ssm];
        getch();
        exit(0);
    }
}
  
Share: 


Didn't find what you were looking for? Find more on PROGRAM TO IMPLEMENT RECURSIVE DESCENT PARSER Or get search suggestion and latest updates.

Adalric Fischer
Adalric Fischer author of PROGRAM TO IMPLEMENT RECURSIVE DESCENT PARSER is from Frankfurt, Germany.
 
View All Articles

 
Please enter your Comment

  • Comment should be atleast 30 Characters.
  • Please put code inside [Code] your code [/Code].

 
No Comment Found, Be the First to post comment!