Predictive Parsing Table for a Small Language Implementation

This assignment presents a C++ implementation of a predictive parser designed for a small language. The code constructs a predictive parsing table based on grammar rules and FIRST/FOLLOW sets. The program processes input to generate the parsing table, which is then used to determine the correct parsing path. The solution includes the generation of the parsing table, including handling cases with '#' (epsilon) productions and follows set calculations. The code also handles the display of the parsing table for analysis. The assignment demonstrates key concepts in compiler design, including lexical analysis, syntax analysis, and the construction of parsing tables, making it a valuable resource for students studying computer science and artificial intelligence.

PREDICTIVE PARSER
#include<iostream>
#include<string.h>
#include<stdlib.h>
#include<ctype.h>
char pr1[7][10]={"A","B","B","C","C","D","D"};
char pr2[7][10]={"B","Cb","Dd","aC","#","Dc","#"};
char pr3[7][10]={"A->B","B->Cb","B->Dd","C->aC","C->#","D >Dc","D->#"};
char first[7][10]={"abcd","ab","cd","a#","#","c#","#"};
char follow[7][10]={"$","$","$","a$","b$","c$","d$"};
char table[5][6][10];
//char pro[i];
int numr(char c)
{
switch(c)
{
case 'A': return 0;
case 'B': return 1;
case 'C': return 2;
case 'D': return 3;
case 'a': return 0;
case 'b': return 1;
case 'c': return 2;
case 'd': return 3;

case '$': return 4;
}
return(2);
}
using namespace std;
int main()
{
int i,j,k,x;
//char pro[10];
clrscr();
for(i=0;i<5;i++)
for(j=0;j<6;j++)
strcpy(table[i][j]," ");
cout<<"\n PREDICTIVE PARSING TABLE FOR SMALL LANGUAGE\n";
for(i=0;i<7;i++)
cout<<pr3[i] << endl ;
cout<<"\n PREDICTIVE PARSING TABLE \n"<< endl;
for(i=0;i<7;i++)
{
k=strlen(first[i]);
for(j=0;j<10;j++)
if(first[i][j]!='#')

strcpy(table[numr(pr1[i][0])+1][numr(first[i][j])+1],pr3[i]);
}
for(i=0;i<7;i++)
{
if(strlen(pr3[i])==1)
{
if(pr2[i][0]=='#')
{
k=strlen(follow[i]);
for(j=0;j<k;j++)
strcpy(table[numr(pr1[i][0])+1][numr(follow[i][j])+1],pr3[i]);
}
}
}
strcpy(table[0][0],"");
strcpy(table[0][1],"a");
strcpy(table[0][2],"b");
strcpy(table[0][3],"c");
strcpy(table[0][4],"d");
strcpy(table[0][5],"$");
strcpy(table[1][0],"A");
strcpy(table[2][0],"B");
strcpy(table[3][0],"C");
strcpy(table[4][0],"D");

cout<<"\n--------------------------------------------------------\n";
for(i=0;i<5;i++)
for(j=0;j<6;j++)
{
cout<<" " << table[i][j]<<" ";
for( x=0; x<(4-strlen(table[i][j])); x++)
cout<<" ";
if(j==5)
cout<<"\n--------------------------------------------------------\n";
}
return 0;
}