Why am I getting this out of range error

Question

I have a file that contains a set range of numbers for example 20. The contents of the file are social security numbers, I am trying to erase every '-'. Though while going through the file I am receiving the following error.

libc++abi.dylib: terminating with uncaught exception of type std::out_of_range: basic_string

Here is the code

string str;
ifstream inFile (fName);
//fName= name of the file
if (inFile.is_open())
{
    while ( getline (inFile,str) )
    {

        cout << str << endl;
        str.erase(3,1);//erasing first '-'
        str.erase(5,1);//erasing second '-'
        cout << str << endl;
    }
    inFile.close();
}

else
    cout << "Unable to open file";

Answer 1

I suggest adding some checks to your code so you don't assume there are two '-' s where you expect to find them.

if ( str.size() >= 4 && str[3] == '-' )
{
   str.erase(3,1);
   if ( str.size() >= 6 && str[5] == '-' )
   {
      str.erase(5,1);
   }
   else
   {
      std::cout << "Did not find a '-' at the 6-th position of the string.\n";
      std::cout << str << std::endl;
   }
}
else
{
   std::cout << "Did not find a '-' at the 4-th position of the string.\n";
   std::cout << str << std::endl;
}