In One Video

Lesson 32
Author : 🦒
Last Updated : November, 2017

C++ Overview

C++ is a general purpose, staticly typed, object oriented programming language that began in 1979 by Danish Computer Scientist Bjarne Stroustrup. For several years the language evolved until it’s official release in 1985.

C++ is essentially an extension of the C programming language. It actually began as a fork of an early pre-standardized C. And while C is not a strict subset of C++ the two languages are largly compatiable and In many instances C code can be used with little or no modification as C++ code.

Becuase C++ is an extension of C, many of the things you can do in C you can also do in C++. But in addition C++ gives you all the power and flexibility of object orientation. So you can use low level system calls, manage memory and deal with pointers. while at the same time working with classes, objects, inheritance and all the features of an object oriented language.

So C++ really lives in two worlds.

How C++ Runs

All c++ programs must utilize a compiler who’s job is to compile the c++ code down into machine code readable by the computer. So anytime you want to run a c++ program you have to compile it first.

C++ relies on the user to manage the program’s memory, although there are garbage collectors avaiable for C++.

Choosing an IDE

Many developers choose to write C++ using a basic text editor, but there are also more specilized integrated development enviornments, some of the most popular include Code Blocks, Eclipse and Net Beans.

Code

Printing

Copycout << "Hello" << endl;
cout << "World";
cout << "!" << endl;

Variables and Data Types

Copy/*
Names are case-sensitive and may begin with:
     letters, _
After, may include
     letters, numbers, _
Convention says
     Start with a lowercase word, then additional words are capitalized
     ex. myFirstVariable
*/
string name = "Mike";    // string of characters, not primitive
char testGrade = 'A';    // single 8-bit character.

// you can make them unsigned by adding "unsigned" prefix
short age0 = 10;         // atleast 16-bits signed integer
int age1 = 20;           // atleast 16-bits signed integer (not smaller than short)
long age2 = 30;          // atleast 32-bits signed integer
long long age3 = 40;     // atleast 64-bits signed integer

float gpa0 = 2.5f;       // single percision floating point
double gpa1 = 3.5;       // double-precision floating point
long double gpa2 = 3.5;  // extended-precision floating point

bool isTall;             // 1 bit -> true/false
isTall = true;

name = "John";

cout << "Your name is " << name << endl;

Casting and Converting

Copycout <<  (int)3.14 << endl;
cout << (double)3 / 2 << endl;

Pointers

Copyint num = 10;
cout << &num << endl;

int *pNum = &num;
cout << pNum << endl;
cout << *pNum << endl;

Strings

Copy#include <string>
string greeting = "Hello";
//      indexes:   01234

cout << greeting.length();
cout << greeting[0] << endl;
cout << greeting.find("llo") << endl;
cout << greeting.substr(2) << endl;
cout << greeting.substr(1, 3) << endl;

Numbers

Copycout << 2 * 3 << endl;       // Basic Arithmetic: +, -, /, *
cout << 10 % 3 << endl;      // Modulus Op. : returns remainder of 10/3
cout << 1 + 2 * 3 << endl;   // order of operations
cout << 10 / 3.0 << endl;    // int's and doubles


int num = 10;
num += 100; // +=, -=, /=, *=
cout << num << endl;

num++;
cout << num << endl;

// Math class has useful math methods
#import <cmath>
cout << pow(2, 3) << endl;
cout << sqrt(144) << endl;
cout << round(2.7) << endl;

User Input

Copystring name;
cout << "Enter your name: ";
cin >> name;
cout << "Hello " << name << endl;

int num1, num2;
cout << "Enter first num: ";
cin >> num1;
cout << "Enter second num: ";
cin >> num2;
cout << "Answer: " << num1 + num2 << endl;

Arrays

Copy// int luckyNumbers[6];
int luckyNumbers[] = {4, 8, 15, 16, 23, 42};
//         indexes:    0  1  2   3   4   5
luckyNumbers[0] = 90;
cout << luckyNumbers[0] << endl;
cout << luckyNumbers[1] << endl;

2 Dimensional Arrays

Copy// int  numberGrid[2][3];
int numberGrid[2][3] = { {1, 2, 3}, {4, 5, 6} };
numberGrid[0][1] = 99;

cout << numberGrid[0][0] << endl;
cout << numberGrid[0][1] << endl;

Vectors

Copy// #include <vector>
vector<string> friends;
friends.push_back("Oscar");
friends.push_back("Angela");
friends.push_back("Kevin");
friends.insert(friends.begin() + 1, "Jim");

// friends.erase(friends.begin() + 1);
cout << friends.at(0) << endl;
cout << friends.at(1) << endl;
cout << friends.at(2) << endl;
cout << friends.size() << endl;

Functions

Copyint addNumbers(int num1, int num2);

int main()
{
     int sum = addNumbers(4, 60);
     cout << sum << endl;

     return 0;
}

int addNumbers(int num1, int num2){
     return num1 + num2;
}

If Statements

Copybool isStudent = false;
bool isSmart = false;

if(isStudent && isSmart){
     cout << "You are a student" << endl;
} else if(isStudent && !isSmart){
     cout << "You are not a smart student" << endl;
} else {
     cout << "You are not a student and not smart" << endl;
}

// >, <, >=, <=, !=, ==
if(1 > 3){
     cout << "number omparison was true" << endl;
}

if('a' > 'b'){
     cout << "character comparison was true" << endl;
}

string myString = "cat";
if(myString.compare("cat") != 0){
     cout << "string comparison was true" << endl;
}

Switch Statements

Copychar myGrade = 'A';
switch(myGrade){
     case 'A':
          cout << "You Pass" << endl;
          break;
     case 'F':
          cout << "You fail" << endl;
          break;
     default:
          cout << "Invalid grade" << endl;
}

While Loops

Copyint index = 1;
while(index <= 5){
     cout << index << endl;
     index++;
}

do{
     cout << index << endl;
     index++;
}while(index <= 5);

For Loops

Copyfor(int i = 0; i < 5; i++){
     cout << i << endl;
}

Exception Catching

Copydouble division(int a, int b) {
   if( b == 0 ) {
      throw "Division by zero error!";
   }
   return (a/b);
}

int main(){
     try {
        division(10, 0);
     } catch (const char* msg) {
      cerr << msg << endl;
     }
     return 0;
}

Classes and Objects

Copyclass Book{
     public:
          string title;
          string author;

          void readBook(){
               cout << "Reading " + this->title + " by " + this->author << endl;
          }
};

Book book1;
book1.title = "Harry Potter";
book1.author = "JK Rowling";

book1.readBook();
cout << book1.title << endl;

Book book2;
book2.title = "Lord of the Rings";
book2.author = "JRR Tolkien";

book2.readBook();
cout << book2.title << endl;

Constructors

Copyclass Book{
     public:
          string title;
          string author;

          Book(string title, string author){
               this->title = title;
               this->author = author;
          }

          void readBook(){
               cout << "Reading " + this->title + " by " + this->author << endl;
          }
};

Book book1("Harry Potter", "JK Rowling");
cout << book1.title << endl;

Book book2("Lord of the Rings", "JRR Tolkien");
cout << book2.title << endl;

Getters and Setters

Copyclass Book{
     private:
          string title;
          string author;
     public:
          Book(string title, string author){
               this->setTitle(title);
               this->setAuthor(author);
          }

          string getTitle(){
               return this->title;
          }
          void setTitle(string title){
               this->title = title;
          }
          string getAuthor(){
               return this->author;
          }
          void setAuthor(string author){
               this->author = author;
          }

          void readBook(){
               cout << "Reading " + this->title + " by " + this->author << endl;
          }
};

Book book1("Harry Potter", "JK Rowling");
cout << book1.getTitle() << endl;

Book book2("Lord of the Rings", "JRR Tolkien");
cout << book2.getTitle() << endl;

Inheritance

Copyclass Chef{
     public:

          string name;
          int age;

          Chef(string name, int age){
               this->name = name;
               this->age = age;
          }

          void makeChicken(){
               cout << "The chef makes chicken" << endl;
          }

          void makeSalad(){
               cout << "The chef makes salad" << endl;
          }

          void makeSpecialDish(){
               cout << "The chef makes a special dish" << endl;
          }
};

class ItalianChef : public Chef{
     public:

          string countryOfOrigin;

          ItalianChef(string name, int age, string countryOfOrigin) : Chef(name, age){
               this->countryOfOrigin = countryOfOrigin;
          }

          void makePasta(){
               cout << "The chef makes pasta" << endl;
          }

          // override
          void makeSpecialDish(){
               cout << "The chef makes chicken parm" << endl;
          }
};

Chef myChef("Gordon Ramsay", 50);
myChef.makeChicken();

ItalianChef myItalianChef("Massimo Bottura", 55, "Italy");
myItalianChef.makeChicken();
cout << myItalianChef.age << endl;

Abstract Classes and Methods

Copyclass Vehicle{
     public:
          virtual void move() = 0;
          void getDescription(){
               cout << "Vehicles are used for transportation" << endl;
          }
};

class Bicycle : public Vehicle{
     public:
          void move(){
               cout << "The bicycle pedals forward" << endl;
          }
};

class Plane : public Vehicle{
     public:
          virtual void move(){
               cout << "The plane flys through the sky" << endl;
          }
};

Plane myPlane;
myPlane.move();