Question

#include <iostream>
#include <string>
#include <fstream>
#include <sstream>

using namespace std;

struct transition{ // transition structure
char start_state, to_state;
char symbol_read;
};

void read_DFA(struct transition *t, char *f, int &final_states, int &transitions){
int i, j, count = 0;
ifstream dfa_file;
string line;
stringstream ss;
dfa_file.open("dfa.txt");
getline(dfa_file, line); // reading final states
for(i = 0; i < line.length(); i++){
if(line[i] >= '0' && line[i] <= '9')
f[count++] = line[i];
}
final_states = count; // total number of final states
// reading transitions
j = 0;
while(getline(dfa_file, line)){
ss.clear();
ss << line;
ss >> t[j].start_state;
ss >> t[j].symbol_read;
ss >> t[j].to_state;
j++;
}
transitions = j; // total transitions
dfa_file.close();
}

void read_input(struct transition *t, char *f, int final_states, int transitions, string input){
char current_state = '0';
int i, j, len = input.length();
bool flag;
for(i = 0; i < len; i++){ // for all input symbols
flag = false;
for(j = 0; j < transitions; j++){ // for all transitions
if(t[j].start_state == current_state && input[i] == t[j].symbol_read){ // if current state and symbol matches with transition
cout<<current_state<<" on "<<input[i]<<" -> "<<t[j].to_state<<endl; // show transition
current_state = t[j].to_state; // update current state
flag = true; // move possible
break;
}
}
if(!flag){ // if no move available from current state with current input symbol
cout<<current_state<<" on "<<input[i]<<" -> "<<"No transition\n";
break;
}
}
flag = false;
// if current state is final state
for(i = 0; i < final_states; i++){
if(current_state == f[i]){
flag = true;
break;
}
}

if(flag)
cout<<"\nAccepted.\n\n";
else
cout<<"\nRejected.\n\n";
}

int main(){
string input;
struct transition *t = new struct transition[100];
char *f_states = new char[50];
int i, final_states, transitions;
read_DFA(t, f_states, final_states, transitions); // read DFA from file
// show final states and transitions
cout<<"Final states: ";
for(i = 0; i < final_states; i++)
cout<<f_states[i]<<" ";
cout<<endl;
cout<< "Transitions:\n";
for(int i = 0; i < transitions; i++)
cout<<t[i].start_state<<" "<<t[i].symbol_read<<" "<<t[i].to_state<<endl;
cout<<endl;
// accept string and check
cout<<"Enter a string (type \"quit\" to stop): ";
cin>>input;
while(input.compare("quit") != 0){
read_input(t, f_states, final_states, transitions, input);
cout<<"Enter a string (type \"quit\" to stop): ";

cin>>input;

}
return 0;
}

Someone posted this code for a DFA stimulator

and text file is

0
0 a 1
0 b 2
1 a 2
1 b 0
2 a 2
2 b 2

Can someone teach me how to run this code and load a text file input in GCC COMPILER IN CODE BLOCKS IDE, IT DOSENT RUN I WANT THIS DFA TO RUN. TEACH ME HOW WITH STEP BY STEP SCREENSHOT PLEASE

Answer 1

First of all to run the program successfully

Create a txt file name as dfa.txt in current directory where you keep your source file DFA.cpp

Once you create the file dfa.txt just copy paste the below text and save it.

0
0 a 1
0 b 2
1 a 2
1 b 0
2 a 2
2 b 2

Compile command : ctrl + shift + f9

НЫ dfa.cpp-Code:Blocks 16.01 File Edit View Search Project Build Debug Fortran wxSmith Tools Tools+ Plugins DoxyBlocks Settings Help <gobal> Start here dfa.cpp X | Projects Symbols Files Workspace #include <string> #include <f.tream> #include く=stream> using namespace std: struct tranaition char start state, to state: char eymbol_read; 10 12 13 14 15 16 17 18 19 20 21 id read DFA (struct transition char f, int final_states, int «transitiona) int i, , count-0 ifstream dfa file: string line: stringstream ฮีฮี; dfa file.open ("tEs 5") getiine (dfa rile, line) tor (i 1<line.length 1++) : 1/ reading inal acaces E[countlineti]: final atatea count; // total number of final 3tate3 Logs& others Code :Blocks X Search results XI Cocc XI Buid log X Buld messages x Aco check x'hcppcheck messages x Acscope X Debugger X Doxy ToDolist: Warning: No to-do types or comment symbols selected to seardh for, nothing to do. ToDoList: Warning: No to-do types or comment symbols selected to search for, nothing to do. D:loppldfa1.cpp NativeParser NativeParser: Finish creating a new parser for project NONE : ProjectNONE parsing stage done! D:cppdfa.cpp Windows (CR+LF) WINDOWS-1252 Li5, Column 21 Insert Read/Write default Paint 圻nclude tind." Sticky Notes cpp il 1:32 AM

Run the program : ctrl + F10

Final Output window:

type string ab

you will get output as Accepted

type string ba

you will get output Rejected.

to exit the program type : quit