ENSC 104: DIGITAL COMPUTER PROGRAMMING

C++ ENVIRONMENT

Readings: Pages 13-15

• Edit - Programs are created in the editor and stored on disk. In BC++, File->New will create a new file to edit  a program. File->Open will open an already existing file for you to do more editing. File-Save As will allow you to save the current file under a different name. Now you will have two copies of the program under two different names.

• Preprocess - The preprocessor is the first step in compiling a C++ program. The preprocessor evaluates all statements that begin with a "#" sign. For example "#include <iostream.h>".

• Compile - The compiler accepts an ASCII file, pgm1.cpp, as input and converts it to object code, pgm1.obj. The output file, pgm1.obj, is commonly referred to as an object module.

• Link - The linker combines or links the object code with all the libraries built into C++ and creates and executable, pgm1.exe, stores this file back out on disk.

• Load - The Loader places the executable from the Link step and places this file into primary memory getting it ready to be executed.

• Execute - The CPU takes each instruction from primary memory and executes that instruction and then fetches the next instruction. The "fetch and execute" is repeated throughout the execution of the program.