Motivation

Just like in many other programming languages, the easiest and most re-invented program is the hello world program. This post shows how to create an Hello World program in Rust.

The main fn

Rust like its pairs uses an entry point for all of its programs, this is the code that executes first before any other when a Rust program is executed.

Function in Rust

A function statement in Rust has the below structure:

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fn name() {
	// Change The World!
}

It starts with the fn keyword followed by the name for the function and a parantheses to take the arguments for the function then a pair of braces for the block of code that should run whenever the function is called/invoked.

The main fn

Rust like its pairs uses an entry point for all of its programs, this is the code that runs first before any other when a Rust program is executed.

The main function declaration looks like this:

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fn main() {
	// Some awesome code
}

Printing to standard output

The hello world program needs to print something to the screen, Rust provides an inbuilt function called println that handles this I/O operation. Its duty is to take whatever value is passed to it and send to the standard output, which is mostly the terminal that the program is running on.

Bringing it together

Having an entry point for the program, also, a function to output to standard output, a useful program can be built.

Hence, a hello world program

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fn main() {
	println!("hello world!");
}

*Ignore the ! after the println statement for now.

Save the code in a file named main.rs then compile using the rustc tool. If you might need to install it.

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rustc main.rs

This will produce an executable binary that can be executed by typing this in the command line.

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./main

And it should output:

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> hello world

Phew!!!