CS201 C++ Notes by Sonu Ilyas

Introduction to Programing (CS201)

Programing:

A programming language is a set of commands, instructions, and other syntax use to create a software program. Languages that programmers use to write code are called "high-level languages." This code can be compiled into a "low-level language," which is recognized directly by the computer hardware.

Syntax:

Every spoken language has a general set of rules for how words and sentences should be structured. These rules are collectively known as the language syntax. In computer programming, syntax serves the same purpose, defining how declarations, functions, commands, and other statements should be arranged.

Program:

Program is a common computer term that can be used as both a noun and a verb. A program (noun) is executable software that runs on a computer. It is similar to a script, but is often much larger in size and does not require a scripting engine to run. Instead, a program consists of compiled code that can run directly from the computer's operating system.

What is C++?

C++ is a cross-platform language that can be used to create high-performance applications.

C++ was developed by Bjarne Stroustrup at Bell labs in 1979, as an extension to the C language.

C++ gives programmers a high level of control over system resources and memory.

The language was updated 3 major times in 2011, 2014, and 2017 to C++11, C++14, and C++17.

Why Use C++

C++ is one of the world's most popular programming languages.

C++ can be found in today's operating systems, Graphical User Interfaces, and embedded systems.

C++ is an object-oriented language which gives a clear structure to programs and allows code to be reused, lowering development costs.

C++ is portable and can be used to develop applications that can be adapted to multiple platforms.

As C++ is close to C# and Java, it makes it easy for programmers to switch to C++ or vice versa

First program:

int main() {

return 0;

Let's break up the following code to understand it better:

Example explained

Line 1: #include <iostream> is a header file library that lets us work with input and output objects, such as cout (used in line 5). Header files add functionality to C++ programs.

Line 2: using namespace std means that we can use names for objects and variables from the standard library.

Line 3: A blank line. C++ ignores white space.

Line 4: Another thing that always appear in a C++ program, is int main(). This is called a function. Any code inside its curly brackets {} will be executed.

Line 5: cout (pronounced "see-out") is an object used to output/print text. In our example it will output " Hello World".

Note: Every C++ statement ends with a semicolon ;.

Note: The body of int main() could also been written as: int main () { cout << " Hello World! "; return 0; }

Remember: The compiler ignores white spaces. However, multiple lines makes the code more readable.