The Rules of Programming

Appendix B. Reading C++ for JavaScript Programmers

The examples in this book are all presented in C++. That’s the language I do most of my programming in, and it’s the language I’m most proficient in.

If you’re a JavaScript programmer, don’t despair—the Rules are still useful! You don’t need to learn how to program in C++ in order to read the examples in this book. Code is code, basically—a loop is a loop, variables are variables, and functions are functions. There are some cosmetic differences, but the basic ideas in this book’s C++ examples translate pretty directly to JavaScript, even when that translation isn’t immediately obvious!

This appendix explains how to do that translation—how to read C++ and convert it in your head to the JavaScript equivalent. You won’t be able to write C++ code after working your way through this appendix—that would take a whole book—but you should be much more capable of reading it.

Types

Time for an example! Here’s a simple function that calculates the sum of an array of numbers, first in JavaScript:¹

function calculateSum(numbers) {

    let sum = 0;

    for (let number of numbers)
        sum += value

    return sum;
}

And then in C++:

int calculateSum(const vector<int> & numbers)
{
    int sum = 0;

    for (int number : numbers)
        sum += number;

    return sum;
}

Um…it’s the same code. Maybe we don’t need an appendix after all.

Or maybe we do. JavaScript syntax was heavily influenced by C syntax, and I won’t have to explain what curly braces and semicolons mean like I ...