Reading The Rust Book from cover to cover — Day 5 — Functions

Functions

Functions in Rust are defined with the keyword fn. The structure and syntax are the same as most of the other languages. Rust uses asnake_case convention for multi-word function names.

Function examples:

fn main() {
    println!("Hello, world!");
    another_function();
    another_function_1(12);
}

//function without paramaters
fn another_function() {
    println!("Another function.");
}

//function with one parameter
fn another_function_1(x: i32) {
    println!("The value of x is: {x}"); //output: The value of x is: 12
}

//function with multiple parameters
fn print_labeled_measurement(value: i32, unit_label: char) {
    println!("The measurement is: {value}{unit_label}");
}

Statements and Expressions in Rust

1. Statements are instructions that perform some action and do not return a value.
2. Expressions evaluate to a resultant value.

Examples of statements: creating a variable, assigning a value to it with a letkeyword as they do not return a value.

Examples of expressions: 5 + 6, calling a function, calling a macro, a new scope block created with {}. Expressions do not contain an ending semicolon, adding a semicolon turns an expression to a…