This is a basic introduction where we learn how to output Hello World! and see the differences between Python and C++

## Main difference in running C++ and Python

• So if you are familiar with python, you know we can easily create a file called hello.py and simply run it with python hello.py
• However for C++, we’ve 1 more step: compiling!
• Create the file hello.cpp
• Compile: g++ hello.cpp -o hello
• Run: ./hello

## Getting started with “Hello World”

You would notice it’s less intuitive compared to Python, but nonetheless similar.

### 6 things to note here.

1. We use // for comments
2. Lines beginning with # are preprocessor commands
• #include: tells preprocessor to dump contents in another file
• <iostream>: file we’re dumping into that defines our IO
3. int main() defines the code when the program starts
• {}: multiple commands in a block
• Think of this as similar to defining a function in Python
4. :: is the scope resolution operator
• It tells the compiler to look for the identifier we want in the namespace (directory of identifiers)
5. cout <<: is the syntax for outputting text
• Intuitively, anything after <<: flows to cout that prints!
• On the other hand, we can get user’s input with cin >>:, see how the data flows in the opposite direction?
6. In the {} block, you must always use a ; after every line.
• This is a common mistake I made when I first started out.

## Variables

We can test the file by running where variable.cpp is the file we saved our above code into:

g++ variable.cpp -o variable
./variable


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