C++

Introduction

TODO

Things I found interesting

Variable initialization

There are 5 common forms of initialization in C++ (see here):

int a;         // default-initialization (no initializer)

// Traditional initialization forms:
int b = 5;     // copy-initialization (initial value after equals sign) --> Inherited from the C language
int c ( 6 );   // direct-initialization (initial value in parenthesis)  --> Not a function! (Starts with a type)
                                                                            Also used when values are explicitly cast
// Modern initialization forms (preferred):
int d { 7 };   // direct-list-initialization (initial value in braces)  --> Disallows narrowing conversions
                                                                            (Only when initializing)
int e {};      // value-initialization (empty braces)                  -- zero-initialization to value 0
                                                                          (Or closest to zero for the type)

As of C++17, the first 3 behave identically in most cases. A significant difference is that direct-list-initialization disallows narrowing conversion:

int w1 { 4.5 }; // compile error: list-init does not allow narrowing conversion

int w2 = 4.5;   // compiles: w2 copy-initialized to value 4
int w3 (4.5);   // compiles: w3 direct-initialized to value 4

Usage of `std::endl` vs `\n` (see here):

std::endl is necessary to indicate that a line of output is a complete thought (and is not completed in another output line somewhere in the code), as well as positioning the cursor on the next line, making them appear where expected.

However, std::endl is often inefficient, since it outputs a newline and flushes the buffer (which is slow). Prefer \n over std::endl when outputting text to the console. When outputting text to the console, we typically don’t need to explicitly flush the buffer ourselves. C++’s output system is designed to self-flush periodically, and it’s both simpler and more efficient to let it flush itself.

std::cout << "x is equal to: " << x << std::endl;                          --> May not be necessary to flush

std::cout << "x is equal to: " << x << '\n'; // single quoted (by itself)  --> Prefered way

Input more than one number at once (see here)::

std::cout << "Enter two numbers separated by a space: ";

int x{}; // define variable x to hold user input (and value-initialize it)
int y{}; // define variable y to hold user input (and value-initialize it)
std::cin >> x >> y; // get two numbers and store in variable x and y respectively

std::cout << "You entered " << x << " and " << y << '\n';

If only a number is entered, the next input of the buffer will be used to fill the second variable.

Function arguments

https://www.youtube.com/watch?v=B_4x7WlQr7M <- good video to watch

C++