C++ Hello World program

When learning a new language, the first program people usually write is one that salutes the world 🙂

Here is the Hello world program in C++.

//include headers; these are modules that include functions that you may use in your
//program; we will almost always need to include the header that
// defines cin and cout; the header is called iostream
#include <iostream>

using namespace std;

int main()
{
  // print output to user
  cout << "Hello World!" << endl;
  return 0;
}

After you write a C++ program you compile it; that is, you run a program called compiler that checks whether the program follows the C++ syntax

if it finds errors, it lists them
If there are no errors, it translates the C++ program into a program in machine language which you can execute

Notes

what follows after // on the same line is considered comment
indentation is for the convenience of the reader; compiler ignores all spaces and new line ; the delimiter for the compiler is the semicolon
all statements ended by semicolon
Lower vs. upper case matters!!
- Void is different than void
- Main is different that main

How to compile?
```
$ g++ hello.cpp –o hello
```
compiler-generated executable file
hello
source file
hello.c
compiling command
g++
Note: the default output filename is “a.out”
How to execute?
```
$ ./hello
```