May 2021

Software Development Life Cycle (SDLC) is the application of standard business practices to building software applications. It’s typically divided into six to eight steps: Planning, Requirements, Design, Build, Document, Test, Deploy, Maintain. Six Phases of the System Development Life Cycle Preliminary Investigation Assesses feasibility and practicality of system System Analysis Study old system and identify

System calls sequence to copy the contents of one file to another file Programming interface to the services provided by the OS Typically written in a high level language (C or C++) Mostly accessed by programs via a high level Application Program Interface (API) rather than direct system call use Three most common APIs are

These are the pieces of the operating system components we’ll be looking at: Process Management Main Memory Management File Management I/O System Management Secondary Management Networking Protection System Command-Interpreter System Process Management A process is a program in execution: (A program is passive, a process active.) A process has resources (CPU time, files) and attributes

Simple Structure MS-DOS written to provide the most functionality in the least space, Operating System Structures. Not divided into modules Although MS-DOS has some structure, its interfaces and levels of functionality are not well separated Layered Approach The operating system is divided into a number of layers (levels), each built on top of lower layers.

API, an abbreviation of application program interface, is a set of routines, protocols, and tools for building software applications. A good API makes it easier to develop a program by providing all the building blocks. A programmer then puts the blocks together. Most operating environments, such as MS-Windows, provide an API so that programmers can

Overloading binary operators can be overloaded just as easily as unary operators. We’ll look at examples that overload arithmetic operators, comparison operators, and arithmetic assignment operators. Arithmetic Operators In the ENGLCON program in before we showed how two English Distance objects could be added using a member function add_dist(): dist3.add_dist(dist1, dist2); By overloading binary operators

Let’s start off by overloading a unary operators. unary operators act on only one operand. (An operand is simply a variable acted on by an operator.) Examples of unary operators are the increment and decrement operators ++ and –, and the unary minus, as in -33. “Objects and Classes,” we created a class Counter to

We noted at the beginning of this chapter that two kinds of strings are commonly used in C++: C-strings and strings that are objects of the string class. In this section we’ll describe the first kind, which fits the theme of the chapter in that C-strings are arrays of type char. We call these strings