Day 02: Teaching myself C++

NOTE:

I’m a self-taught programmer, who recently started a new adventure to learn C++ by reading a ton of other people’s code and language documentations. This method might not work for all the people. Beacause it requires a certain degree of experience in a low-level or a mid-level programming language like C in order to read and learn a language like C++ from other people’s code and language documentations. For me this was possible because, I had some experience using C which I learned for the course CS50x. First, I started with the scripts that Daniel Gakwaya, had released in his github repository The C 20 Masterclass source code. I will compose this blog post to demonstrate the lessons I learnt on my second day of analyzing his scripts.

1. Type of Initializers

1.1 Braced Initializers

    //Braced initializers
    
    //Variable may contain random garbage value . WARNING
    int elephant_count;
    
    int lion_count{};//Initializes to zero
    
    int dog_count {10}; //Initializes to 10
    
    int cat_count {15}; //Initializes to 15
    
    //Can use expression as initializer
    int domesticated_animals { dog_count + cat_count };

    std::cout << "Elephant count : " << elephant_count << std::endl;
    std::cout << "Lion count : " << lion_count << std::endl;
    std::cout << "Dog count : " << dog_count << std::endl;
    std::cout << "Cat count : " << cat_count << std::endl;
    std::cout << "Domesticated animal count : " << domesticated_animals << std::endl;

1.2 Functional Initialization

   //Functional Initialization
    int apple_count(5);
    int orange_count(10);
    int fruit_count (apple_count + orange_count);
    //int bad_initialization ( doesnt_exist3 + doesnt_exist4 );

    //Information lost. less safe than braced initializers
    int narrowing_conversion_functional (2.9);
    
    
    std::cout << "Apple count : " << apple_count << std::endl;
    std::cout << "Orange count : " << orange_count << std::endl;
    std::cout << "Fruit count : " << fruit_count << std::endl;
    std::cout << "Narrowing conversion : " << narrowing_conversion_functional << std::endl;//Will loose info

2. Types of Integers

signed : Signed variables can store negative, zero, and positive numbers.

range of possible values : [-2147483648 to 2147483647]

unsigned : Unsigned variables can store the number zero and positive numbers

range of possible values : [0 to 4294967295]

Types of integers:

short int
int
long int
long long int

Type	Size (in bytes)	Range
signed short int	2	-32,768 to 32,767
unsigned short int	2	0 to 65,535
signed int	4	[-2147483648 to 2147483647]
unsigned int	4	[0 to 4294967295]
signed long int	8	-2,147,483,648 to 2,147,483,647
unsigned long int	8	0 to 4,294,967,295
signed long long int	8	-(2^63) to (2^63)-1
unsigned long long int	8	0 to 18,446,744,073,709,551,615

3. Types of fractional Numbers

Types of fractional numbers:

float
double
long double

Type	Size (in bytes)	Range	Digits of precision
float	4	3.4 x 10^-38 to 3.4 x 10⁺³⁸	7
double	8	1.7×10^-308 to 1.7×10⁺³⁰⁸	15
long double	16	1.7×10^-308 to 1.7×10⁺³⁰⁸	18

4. If Statement

#include <iostream>

int main(){

    bool red_light {false};
    bool green_light{true};
    
    if(red_light == true){
        std::cout << "Stop!" << std::endl;
    }else{
        std::cout << "Go through!" << std::endl;
    }

    if(green_light){
        std::cout << "The light is green!" << std::endl;
    }else{
        std::cout << "The light is NOT green!" << std::endl;
    }

    return 0;
}

5. Type Casting

#include <iostream>

int main(){
    char value = 65 ; // ASCII character code for 'A'
    std::cout << "value : " << value << std::endl; // A
    std::cout << "value(int) : " << static_cast<int>(value) << std::endl; 

    return 0;
}

6. Integer modifier suffixes

    auto var6 { 123u}; // unsigned
    auto var7 { 123ul}; //unsigned long
    auto var8 { 123ll}; // long long

Thats it for day 2, hope you enjoyed the content.

Tags: /cpp/ /c++/