SP Practical 4

Practical : 4

Subject : System Programming

Aim : C++ program to remove the Left Recursion from a given grammar.

Source Code :

#include<stdio.h>

#include<string.h>

void main()

{

char a[20],b[20],c[20],nt;

            int i,j;

            printf("\nenter equation :");

            gets(c);

            nt=c[0];

            i=3;

            if(nt==c[i])

                        printf("left recursion\n");

            else

                        printf("not");

            for(i=3;c[i]!='\0';i++)

            {

                        while(c[i]!='|')

                        {

                             if(c[i]==nt)

                             {

                                    i++;

                                    printf("%c` -> ",nt);

                                    while(c[i]!='|')

                                    {

                                                printf("%c",c[i]);

                                                if(c[i]=='\0')

                                                {

                                                            printf("%c`\n",nt);

                                                            printf("%c -> E",nt);

                                                            exit(0);

                                                }

                                                i++;

                                    }

                                    printf("%c`\n",nt);

                             }

                             else

                             {

                                    printf("%c -> ",nt);

                                    while(c[i]!='|')

                                    {

                                                printf("%c",c[i]);

                                                if(c[i]=='\0')

                                                {

                                                            printf("%c`\n",nt);

                                                            printf("%c -> E",nt);

                                                            exit(0);

                                                }

                                                i++;

                                    }

                                    printf("%c`\n",nt);

                             }

                        }

            }

            printf("%c->E",nt);

}

Output :