max array size?

[nokci]

i am writing a code to create a 2600 * 1000 array after reading a .txt document that is filled with random letters (2.4 mb of random letters). When i try to run the program it just halts and none of my check points show up (cout << "a";). here is my code:

         string key="C:\\key.txt";
         ifstream inFile;
         int i=0;
         int j=0;
         const int ROW = 2600;
         const int COL = 1000;
         char keyarray[ROW][COL];
         char ch;         
         
         cout << "ab";
         inFile.open(key.c_str());
         
         if (inFile.fail())
         {
                           cout << "not properly opened";
                           exit(1);
         }
         
         
         cout << "bc";
         
         for (j=0; j<=ROW; j++)
         {
             cout << "a";
             for (i=0; i <= COL; i++)
             {
                 cout << "c";
                 inFile.get(ch);
                 keyarray[j][i]=ch;
                 cout << keyarray[j][i];
                 cout << "d";
             }
         }

[Banfa]

Are you sure? Did you check the hard disk light? Did you check the Task Manager? May be it just paused to allocate that array of yours keyarray which is rather large.

[Dheeraj Joshi]

Does your code has a main function and include statements? or you ignored them while posting assuming we will consider it while reading?

Regards
Dheeraj Joshi

[nokci]

Does your code has a main function and include statements? or you ignored them while posting assuming we will consider it while reading?

Regards
Dheeraj Joshi

i just ignored them to save space

[nokci]

Are you sure? Did you check the hard disk light? Did you check the Task Manager? May be it just paused to allocate that array of yours keyarray which is rather large.

it crashes when i run it and if i try to debug its says : "An access violation (segmentation fault) raised in your program"

[jkmyoung]

?Guessing it's a memory problem? Perhaps the program continually asks for more memory and waits until it gets it, (which it won't.) There could be a delay opening the file you're asking for.

Have you tried and run with a smaller array? eg 260 X 1000 or even 260 X 200?

Also, do you really need to store all the data to process it, or can you use some sort of stream instead?

[Banfa]

The error may well be on lines 22 and 25. The loop conditions are causing you to access data outside the boundaries of the array.

If you declare an array with dimension N int array[N]; for example then the valid array indexes are in the range 0 to N - 1 that is in the declaration you request the actual number of entries in the array and those entries are numbered from 0.

Your loop conditions cause j to have values in the range 0 to ROW and j to have values in the range 0 to COL.

When either j == ROW or i == COL you therefore are accessing data outside the object keyarray.

That could easily cause a segmentation fault and is certainly undefined behaviour.