Intro to C++ Part 1

Intro

• Every code must be written in main() function.
  • main() function is the entry point of the C++
  • Code in main() is the first to be executed

    #include

• Directive
• Used to include head files.
  • Head files contains declarations of functions and objects that program can use.
• #include <iostream> includes the iostream header, which provides objects like std::cout for outputting text to the console.

Variables

• Hold data values.
• Store, manipulate, display informations.
• Initialize variable.

  Vaiable_type Variable_name = value;

• int --> represents whole numbers.
• float || double --> represents real numbers.
  • float --> decimal numbers // up to 7 decimal digits.
  • double --> with more precisions // up to 15 - 17 decimal digits.

    float variable_name = 99.99f;

String

• To use string in C++, include <string> should be added on top of the code.
  2 ways to implement
  1. Adding using namespace std; after the #include <string>
  2. std::string cariable_name = "This is a string."

     #include <string>
       using namespace std; // method 1
       int main() {
     		 string s1 = "Hello."; // method 1
         std::string s2 = "Hello."; // method 2
         return 0;
      	}

Boolean

• Only 2 possible values, true || false

  bool variable_true = true;
  bool variable_false = false;

• When printing boolean values using cout, true --> 1 false --> 0

Char

• Represents single character
• keyword = char

  char variable_name = 'h';

Constants // Keyword const

• Variables that can't be changed once it's intialized.
  const int max_value = 100;
  - max_value can't be changed.