Pakhi_DFA

#include <stdio.h>
#define TOTAL_STATES 7
#define FINAL_STATES 5
#define ALPHABET_CHARCTERS 2
#define UNKNOWN_SYMBOL_ERR 0
#define NOT_REACHED_FINAL_STATE 1
#define REACHED_FINAL_STATE 5
enum DFA_STATES{q0,q1,q2,q3,q4,q5,q6};
enum input{a,b};
int Accepted_states[FINAL_STATES]={q0,q1,q2,q3,q4};
char str[];
long cnt=0;
long cnt1=0;
char alphabet[ALPHABET_CHARCTERS]={'a','b'};
int Transition_Table[TOTAL_STATES][ALPHABET_CHARCTERS];
int Current_state=q0;
void DefineDFA()
{
    Transition_Table[q0][a] = q1;
    Transition_Table[q0][b] = q5;
    Transition_Table[q1][a] = q2;
    Transition_Table[q1][b] = q5;
    Transition_Table[q2][a] = q3;
    Transition_Table[q2][b] = q5;
    Transition_Table[q3][a] = q4;
    Transition_Table[q3][b] = q5;
    Transition_Table[q4][a] = q6;
    Transition_Table[q4][b] = q5;
    Transition_Table[q5][a] = q6;
    Transition_Table[q5][b] = q0;
    Transition_Table[q6][a] = q6;
    Transition_Table[q6][b] = q6;

}
int DFA(char current_symbol)
{
int i,len;
    for(len=0;len<ALPHABET_CHARCTERS; len++)
        if(current_symbol==alphabet[len])
            break;//stops if any character other than a or b
    if(len==ALPHABET_CHARCTERS)
         return UNKNOWN_SYMBOL_ERR;
    for(i=0;i<FINAL_STATES;i++)
 if((Current_state=Transition_Table[Current_state][len])
==Accepted_states[i])
            return REACHED_FINAL_STATE;
    return NOT_REACHED_FINAL_STATE;
}
int main(void)
{
    char current_symbol;
    int result;

    DefineDFA();    //Fill transition table

    printf("Enter a string :\n");

string s
    cin>>s
    int a=0,b=0;
    for(int i=0;i<s.size();i++)
    {
    if(s[i]=='a') a++
        else b++;
    }
    if(a>4||b%2) cout<"Invalid"<<endl
    else cout<<"Valid"<<endl;

    return 0;
}