Program to accept a string (ab)*b*/

#include<iostream.h>

#include<conio.h>

#include<string.h>

enum position{true,false};

int main()

{

    clrscr();

    enum position postn=true;

    char*str;

    cout<<"Place an input string:: ";

    cin>>str;

    int lng=strlen(str);

    for(int count=0;count<lng-1;count++)

    {

            if(*str=='a' && count%2==0)

            {

            postn=true;

            }

            else if(*str=='b' && count%2==1)

            {

            postn=true;

            }

            else if(*str=='a' && count%2==1)

            {

                postn=false;

                break;

            }

          str++;

    }

    if(*str=='b' && postn==true)

    {

      cout<<"\nInput string belongs to the given grammar";

    }

    else

            cout<<"\nInput string does not belong to given grammar";

            getch();

            return 0;

}