Introduction

C++ is one of the world's most popular programming languages.It is a cross-platform language that can be used to create high-performance applications.

C++ was developed by Bjarne Stroustrup, 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.

Prerequisites

This guide assumes you have the following basic background:

  • A general understanding of the Internet and the World Wide Web (WWW).
  • Some programming experience in any language will be helpful.

C++

C++ is an object-oriented programming language which gives a clear structure to programs and allows code to be reused, lowering development costs. C++ can be found in today's operating systems, Graphical User Interfaces, and embedded systems.

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.

A sample program:

#include
using namespace std;
int main() {
cout << "Hello World!";
return 0;
}

Variables

A variable provides us with named storage that our programs can manipulate. Each variable in C++ has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable.

The name of a variable can be composed of letters, digits, and the underscore character. It must begin with either a letter or an underscore. Upper and lowercase letters are distinct because C++ is case-sensitive.

There are following basic types of variable in C++

  1. bool - Stores either value true or false.
  2. char - Typically a single octet (one byte). This is an integer type.
  3. int - The most natural size of integer for the machine.
  4. float - A single-precision floating point value.
  5. double - A double-precision floating point value.
  6. void - Represents the absence of type.
  7. string - A string type

Some valid declarations are shown here −

int i, j, k;
char c, ch;
float f, salary;
double d;


Scope

In general, the scope is defined as the extent up to which something can be worked with. In programming also the scope of a variable is defined as the extent of the program code within which the variable can we accessed or declared or worked with.

There are mainly two types of variable scopes:

  1. Local Scope- Variables defined within a function or block are said to be local to those functions.
  2. Global scope- Global Variables can be accessed from any part of the program.

Sample Code:

#include
using namespace std;
//global variable
int global=5;
//main function
int main(){
//local variable
int local=2;
}

Functions

A function is a block of code which only runs when it is called.You can pass data, known as parameters, into a function.

Functions are used to perform certain actions, and they are important for reusing code: Define the code once, and use it many times.

The C++ standard library provides numerous built-in functions that your program can call. For example, function strcat() to concatenate two strings, function memcpy() to copy one memory location to another location and many more functions.

Function Declarations
Calling a Function
Function Arguments

Syntax

void myFunction() {
// code to be executed
}

Condition-Statements

Conditional statements, also known as selection statements, are used to make decisions based on a given condition. If the condition evaluates to True, a set of statements is executed, otherwise another set of statements is executed.

The if Statement: The if statement selects and executes the statement(s) based on a given condition. If the condition evaluates to True then a given set of statement(s) is executed. However, if the condition evaluates to False, then the given set of statements is skipped and the program control passes to the statemen.

The if-else Statement: The if – else statement causes one of the two possible statement( s) to execute, depending upon the outcome of the condition

if (condition) {
// block of code to be executed if the condition is true
}
else if (condition) {
// block of code to be executed if the condition is true
}
else{
// block of code to be executed if the condition is false
}