An identifier is a user defined name; variable names are identifiers. Identifiers must not be spelled the same as keywords such as if and while; for example, you cannot create a variable with the name while.
A keyword is a word defined in the C++ language such as if and while. It is illegal to define an identifier such as a variable name that is spelled the same as a keyword.
The C++ standard library is a collection of code defined by the ISO (International Standards Organization) that must be included with every standards-compliant compiler. Unfortunately, as of this writing, there are no completely standards-compliant compilers, but the one on the CD in the back of the book should be close enough for programs you will be writing.
A C string literal is a literal value representing a variable number of characters. An example is “This is a test.”. C string literals are surrounded by double quotes (“).
A block is a section of code that acts like one statement, as far as the language is concerned; that is, wherever a statement can occur, a block can be substituted, and it will be treated as one statement for the purposes of program organization.