Programming/C++/Syntax

Note: Common File Extensions: .cpp .h

Compiling C++

To run any C++ code, it must first be compiled.

To do this, in terminal, cd to the desired directory and run g++ <path_to_file> -o <name_of_file_to_create>.

This will generate a new executable file, based on the compiled code.
Run this file via ./<name_of_created_file>.

Comments

Inline Comments

// This is an inline comment.

Block Comments

/**
 *This is a block comment.
 *Comment line 2.
 *Another block comment line.
 */

Basic Input and Output

Basic Output

A very basic output example is:

#include <iostream>

std::cout << "Hello World!\n";

We can also chain together strings this way:

#include <iostream>

std::cout << "Hello " << "World!" << "\n";

If we exclude the \n, then output will remain on a single line:

#include <iostream>

std::cout << "Hello ";
std::cout << "World!";
std::cout << "\n";

The above code snippets are all functionally equivalent.

Basic Input

Similar to basic output:

#include <iostream>

std::cin >> <variable_here>

For example:

#include <iostream>

// This will read in a string as a variable, then immediately display it.
string my_string;
std::cin >> my_string;
std::cout << my_string << "\n";

Variables

Variables are strongly typed in C++. That means you must declare the type as well as the name.

Variable Definition

bool a_bool = true;
bool b_bool = false;
string my_var_1 = "This is ";
string my_var_2 = "a string.";

Variable Usage

#include <iostream>

std::cout << "Printing variable values.\n";
std::cout << a_bool << "\n";
std::cout << b_bool << "\n";
std::cout << my_var_1 << my_var_2 << "\n";

Booleans

C++ uses the following bools"

bool true_bool = true;
bool false_bool = false;

Null Values

C++ uses the standard null.

int null_value = null;