C++ const casting

I am trying to print the value of a const but it is not working. I am making a return to C++ after years so I know casting is a possible solution but I can't get that working either.

The code is as follows:

  //the n开发者_开发技巧umber of blanks surrounding the greeting
    const int pad = 0;

    //the number of rows and columns to write
    const int rows = pad * 2 + 3;
    const string::size_type cols    =       greeting.size() + pad * 2 + 2;

    cout << endl << "Rows : " + rows;

I am trying to print the value of 'rows' without success.

You want:

cout << endl << "Rows : " << rows;

Note this has nothing to do with const - C++ does not allow you to concatenate strings and numbers with the + operator. What you were actually doing was that mysterious thing called pointer arithmetic.

You're almost there:

cout << endl << "Rows : " << rows;

The error is because "Rows : " is a string literal, thus is a constant, and generally speaking is not modified as you may think.

Going slightly further, you likely used + (colloquially used as a concatenation operation) assuming you needed to build a string to give to the output stream. Instead operator << returns the output stream when it is done, allowing chaining.

// It is almost as if you did:
(((cout << endl) << "Rows : ") << rows)

I think you want:

std::cout << std::endl << "Rows : " << rows << std::endl;

I make this mistake all the time as I also work with java a lot.

As others have pointed out, you need

std::cout << std::endl << "Rows : " << rows << std::endl;

The reason (or one of the reasons) is that "Rows : " is a char* and the + operator for char*s doesn't concatenate strings, like the one for std::string and strings in languages like Java and Python.