Question

Slight issue. (Not using toupper() and tolower() functions) I understand what converting to uppercase and lowercase using numerical values is but following my C++ book, why is the conversion at the end of this statement and not before?:

if (letter >= 'A')  //test for 'A' or larger
    if (letter <= 'Z')  //test for 'Z' or smaller
    {
        cout << endl
             << "You entered a capital letter."
             << endl;
        letter += 'a' - 'A'; //Convert to lowercase
        return 0;
    }

if (letter >= 'a') //test for 'a' or larger
{
    if (letter <= 'z') //test for 'z' or smaller
    {
    cout << endl
         << "You entered a small letter."
         << endl;

    return 0;
    }
}

Why would it convert the uppercase to lowercase at this point of code execution since the second if statement deals with lowercase input?

Answer 1

Why would it convert the uppercase to lowercase at this point of code
execution since the second if statement deals with lowercase input?

That is because

return 0

means that the function is finished. The lines

if (letter >= 'a') //test for 'a' or larger
{
    if (letter <= 'z') //test for 'z' or smaller
    {
    cout << endl
         << "You entered a small letter."
         << endl;

    return 0;
    }
}

will not be executed if letter was originally an upper case letter. It would print out “You entered a capital letter.”, then convert it to lower case, then exit.

why is the conversion at the end of this statement and not before?

It would make no difference if the conversion were before the cout statement.