SEM6:TOC Expt2-DFA

#include "stdafx.h"

#include<iostream>

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{

    char str[100];
    cout<<"Enter string";
    cin>>str;

    int i=0;
    int q=0;
    while(str[i])
    {
        switch(q)
        {
        case 0:
            if(str[i]=='a')
                q=1;
            break;
        case 1:
            if(str[i]=='a')
                q=1;
            if(str[i]=='b')
                q=2;
            if(str[i]=='c')
                q=0;
            break;
        case 2:
            if(str[i]=='a')
                q=1;
            if(str[i]=='b')
                q=0;
            if(str[i]=='c')
                q=3;
            break;
        case 3:
            if(str[i]=='a')
                q=4;
            if(str[i]=='b')
                q=3;
            if(str[i]=='c')
                q=3;
            break;
        case 4:
            if(str[i]=='a')
                q=4;
            if(str[i]=='b')
                q=5;
            if(str[i]=='c')
                q=3;
            break;
        case 5:
            if(str[i]=='a')
                q=4;
            if(str[i]=='b')
                q=3;
            if(str[i]=='c')
                q=0;
            break;
        }
        i++;
    }


    if(q==3 || q==4 ||q==5)
        cout<<"\n String is valid";
    else
        cout<<"\n String is invalid ";






    return 0;


}