I'm getting a "subscript out of range error" everytime I debug this code. Can someone please help me pinpoint the error or errors?

Question

I've checked all my strings and arrays. Nothing looks wrong to me. My include statements may be the problem. Perhaps I am missing one. I'm am a novice programmer. So I am clueless as to why this code will not work. It looks right and should absolutely work.

#include<iostream>
#include<cstdlib>
#include<ctime>
#include<fstream>
#include<string>
using namespace std;

int main()
{
        int i;
        char response;
        char answers[20];
        char uresponse[20];
        int score=0;


        srand(time(0));
        int test_num = rand() % 2+1;
//        cout << test_num << endl;
        if (test_num == 1)
        {
                string line;
                ifstream myfile ("form1.txt");
                getline (myfile,line);
//                cout<< line<<endl;
                for (int i = 0; i <= 19; i++)
                {
                        answers[i] = line[i*2];
//                        cout<<answers[i]<<endl;
                }
                getline (myfile,line);

                  if ( myfile.is_open())
                  {
                          int x = 0;
                        while ( myfile.good() )
                        {
                          char answers[20];
                              string line;
                                getline (myfile,line);
//                                cout<< line << endl;
                                if( line == "")
                                {
                                        cout << "Enter answer: ";
                                        cin >> response;
                                        if(response == 'a', 'A' || response == 'b', 'B' || response == 'c', 'C' || response == 'd', 'D')
                                        {
                                                response = response;
                                        }
                                        else
                                        {
                                                cout << "ERROR. You must enter A, B, C, or D. Please re-enter: ";
                                                cin >> response;
                                        }
                                        response = toupper(response);
                                        uresponse[x] = response;
                                        x++;
                                }
                        }
//                      cout << uresponse <<endl;
//                      system("pause");
                 }
                  else
  {
          myfile.close();
  }
        }
        else
                {
                string line;
                ifstream myfile ("form2.txt");
                getline (myfile,line);
 //               cout<< line<<endl;
                for (int i = 0; i <= 19; i++)
                {
                        answers[i] = line[i*2];
//                        cout<<answers[i]<<endl;
                }
                getline (myfile,line);

                  if ( myfile.is_open())
                  {
                        int x = 0;
                        while ( myfile.good() )
                        {
                          char answers[20];
                              string line;
                                getline (myfile,line);
 //                               cout << line << endl;
                                if( line == "")
                                {
                                        cout << "Enter answer:";
                                        cin >> response;
                                        if(response == 'a', 'A' || response == 'b', 'B' || response == 'c', 'C' || response == 'd', 'D')
                                        {
                                                response = response;
                                        }
                                        else
                                        {
                                                cout << "ERROR:You must enter A, B, C, or D. Please re-enter:";
                                                cin >> response;
                                        }
                                        response = toupper(response);
                                        uresponse[x] = response;
                                        x++;
                                }
                        }
//                      cout<<uresponse<<endl;
//                    system("pause");
                 }
                  else
  {
          myfile.close();
  }
        }

        for (int j=0; j<20; j++)
        {
                if (answers[j] == uresponse[j])
                        score += 1;
        }

        if(score >15)
        {
                cout << "CONGRATULATIONS! You Passed with a score of ";
                cout << score << endl;
                system("pause");
        }
        else
        {
                cout<< "You Failed with a score of ";
                cout << score << endl;
                system("pause");
        }
        system("pause");
        return 0;
        }`enter code here`

Lews Therin · Accepted Answer · 2012-10-14T20:30:36.133

3

This could be the culprit:

answers[i] = line[i*2];

Are you certain i*2 is not >= line.size()?

Btw, this code looks dodgy:

if(response == 'a', 'A' || response == 'b', 'B'
 || response == 'c', 'C' || response == 'd', 'D')
{
     response = response   
}

Perhaps you want to use a switch and initializing response to itself.. why?

EDIT: And your while(myfile.good()) That probably executes 100 times and you keep incrementing x It's hard to say in your code.. you have a lot of "dodgy" lines :P

edited Oct 14 '12 at 20:30

answered Oct 14 '12 at 20:15

Lews Therin

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I understand how this would pose a problem. Thank you. I corrected this and several other errors(which have nothing to do with the out of range error). But still, "subscript out of range" every time. Also I am using Visual Studio 2012. My lab partner uses a different version, an earlier one. We developed the code in his version. Could this have something to do with it? – user1745480 Oct 14 '12 at 20:27
@user1745480 See my updated answer. Looks like debugging is in order. I kindly suggest you get a debugger and learn to use it :) – Lews Therin Oct 14 '12 at 20:31
Thanks. But i warned you I was novice. Anyway what if I added the statement 'x < 127' on line 60 and 'x < 118' on line 108. These numbers are equivalent to the number of lines in each text file I am opening. – user1745480 Oct 14 '12 at 20:41
But x would still exceed the size of elements you have for response. To make your life easy use a resizable array. Or a vector. Then you don't have to worry about bounds :) – Lews Therin Oct 14 '12 at 20:44

I'm getting a "subscript out of range error" everytime I debug this code. Can someone please help me pinpoint the error or errors?

1 Answers1