A textbook or similarly detailed reference is essential for serious study of C or C++. Go with the masters: The C Programming Language, second edition, by Brian Kernighan and Dennis Ritchie [1], is an excellent, manageable resource for the basics of procedural programming, while The C++ Programming Language, by Bjarne Stroustrup [4], is a definitive, encyclopedaic reference.
C++ is a powerful, complex language whose syntax is similar to that of C, or to the scripting languages of Maple and Mathematica. An ePiX input file is source code for a C++ program that writes an eepic file as output. ePiX may be viewed as an extension to C++; in the same way that LATEX furnishes a high-level interface to TEX, ePiX provides a high-level bridge between the computational power of C++ and the LATEX picture environment.
Like all high-level programming languages, C++ provides variables, functions, and control structures. Variables hold pieces of data such as numerical values and geometric locations, while functions operate on data. A control structure, such as a loop or conditional statement, affects the program's course according to the program's current state. A source file is composed primarily of ``statements'', which perform actions ranging from defining variables and functions to setting figure attributes, performing calculations, and writing objects to the output file.