//In C++ Finish the Program

#include

#include

#include

#include

using namespace std;

//--------------------------------------

// CS421 File td.cpp for HW2B Table-Driven Scanner

// Your name: **

//--------------------------------------

// Complete this to fit the HW2B specification - look for **

// Must have the same types of tracing couts as my demo program.

// info on each DFA

struct info

{

string name; // token name

int startstate;

int finalstate;

};

info DFAs[4]; // store up to 4 dfas' start and final

int TRS[10][4]; // store all trs's - states 0-9 and chars a b c d -- all dfas transitions are in here

// ----- utility functions -----------------------

int readTables()

{

ifstream fin ("trs.txt", ios::in);

ifstream fin2 ("dfas.txt", ios::in);

// ** Read in the files into TRS and DFAs

// ** Return how many DFAs were read

}

void displayTables(int numDFAs)

{

// ** display DFAs nicely labeled

// ** display TRS nicely labeled

}

bool accept(info dfa, string word)

{

// ** Does the dfa accept the word?

// Start with the start state of the DFA and

// look up the next state in TRS for each char in word.

// At the end of the word, make sure you are in the

// final state of the DFA.

// Use a formula to convert chars to TRS col numbers.

}

int main()

{

cout << "This is a table driven scanner. Needs trs.txt and dfas.txt." << endl;

cout << "States are 0 to 9 and chars are a to d" << endl;

int numDFA = readTables(); // how many DFAs were read

displayTables(numDFA); // DISPLAY TABLES

cout << ".....done reading tables...." << endl;

string word;

while(true)

{ cout << "@@Enter a string: " ;

cin >> word;

// ** try the DFAs one by one and see

// if the word is accepted

// if so, display the word and the token name

// ** if no DFA does, generate a lexical error message.

cout << "do control-C to quit" << endl;

}

}//the end

TEST FILE: dfas.txt

token1 0 1

token2 2 3

TEST FILE: trs.txt

0 1 -1 -1

-1 -1 -1 -1

-1 -1 2 3

-1 -1 -1 -1

-1 -1 -1 -1

-1 -1 -1 -1

-1 -1 -1 -1

-1 -1 -1 -1

-1 -1 -1 -1

-1 -1 -1 -1

Strings that are Entered: ab

abb

aaab

cd

cdd

cccd

DESIRED OUTPUT:

This is a table driven scanner. Needs trs.txt and dfas.txt.

States are 0 to 9 and chars are a to d

a b c d

State 0: 0 1

State 1:

State 2: 2 3

State 3:

State 4:

State 5:

State 6:

State 7:

State 8:

State 9:

token1: 0 is start and ends in 1

token2: 2 is start and ends in 3

.....done reading tables....

@@Enter a string: ab

Trying dfa 0--------

state: 0 char: a

new state: 0

state: 0 char: b

new state: 1

Found token token1

do control-C to quit

@@Enter a string: abb

Trying dfa 0--------

state: 0 char: a

new state: 0

state: 0 char: b

new state: 1

state: 1 char: b

new state: -1

Trying dfa 1--------

state: 2 char: a

new state: -1

Lexical error!

do control-C to quit

@@Enter a string: aaab

Trying dfa 0--------

state: 0 char: a

new state: 0

state: 0 char: a

new state: 0

state: 0 char: a

new state: 0

state: 0 char: b

new state: 1

Found token token1

do control-C to quit

@@Enter a string: cd

Trying dfa 0--------

state: 0 char: c

new state: -1

Trying dfa 1--------

state: 2 char: c

new state: 2

state: 2 char: d

new state: 3

Found token token2

do control-C to quit

@@Enter a string: cdd

Trying dfa 0--------

state: 0 char: c

new state: -1

Trying dfa 1--------

state: 2 char: c

new state: 2

state: 2 char: d

new state: 3

state: 3 char: d

new state: -1

Lexical error!

do control-C to quit

@@Enter a string: cccd

Trying dfa 0--------

state: 0 char: c

new state: -1

Trying dfa 1--------

state: 2 char: c

new state: 2

state: 2 char: c

new state: 2

state: 2 char: c

new state: 2

state: 2 char: d

new state: 3

Found token token2

do control-C to quit

@@Enter a string: ^C