title: Reading in numbers from a file into an array
body: <p>So I have a file with three columns in e.g:</p>
  
  <pre><code>1 1 750
  </code></pre>
  
  <p>These are x,y,intensity values.</p>
  
  <p>Then I try to read in this long file into arrays. This is the code so far:</p>
  
  <pre><code>using std::cout;
  using std::endl;
  using std::string;
  
  string fOutFileName("gaintest.root"); 
  
  
  int main()
  {
  
    std::ifstream file1("data_p30.dat");
  
    double intensity;
    int i;
    int j ;
    double c[1000][1000];
  if (file1.is_open()) {
      file1.seekg(0);
      while (!file1.eof()) {
        file1 &gt;&gt; i &gt;&gt; j &gt;&gt; intensity;
        c[i][j]=intensity;
        cout&lt;&lt;c[i][j]&lt;&lt;'/n'; 
      }
      file1.close();
    } else cout &lt;&lt; "Error, cannot open file 1";
  }
  </code></pre>
  
  <p>So ultimately I want to be able to have a 2D array that is linked to the intensity. Any ideas on why I am failing? It compiles fine but when it run, it looks like this:</p>
  
  <pre><code>root [0] 
   *** Break *** segmentation violation
  
  
  
  ===========================================================
  There was a crash.
  This is the entire stack trace of all threads:
  ===========================================================
  #0  0x0000003701098c05 in waitpid () from /lib64/libc.so.6
  #1  0x000000370103c481 in do_system () from /lib64/libc.so.6
  #2  0x00002b036f5ebc6a in TUnixSystem::StackTrace() ()
     from /batchsoft/root/root528-x86_64-slc5-43/lib/libCore.so
  #3  0x00002b036f5eb63c in TUnixSystem::DispatchSignals(ESignals) ()
     from /batchsoft/root/root528-x86_64-slc5-43/lib/libCore.so
  #4  &lt;signal handler called&gt;
  #5  0x00002b0370acd515 in TRint::Run(bool) ()
     from /batchsoft/root/root528-x86_64-slc5-43/lib/libRint.so
  #6  0x000000000040106d in main ()
  ===========================================================
  
  
  The lines below might hint at the cause of the crash.
  If they do not help you then please submit a bug report at
  http://root.cern.ch/bugs. Please post the ENTIRE stack trace
  from above as an attachment in addition to anything else
  that might help us fixing this issue.
  ===========================================================
  #5  0x00002b0370acd515 in TRint::Run(bool) ()
     from /batchsoft/root/root528-x86_64-slc5-43/lib/libRint.so
  #6  0x000000000040106d in main ()
  ===========================================================
  </code></pre>