RUST연습]Rust Crash Course | Rustlang -44:47부터

main.rs

// mod print;
// mod vars;
// mod types;
mod strings;

fn main() {
    // print::run();
    // vars::run();
    // types::run();
    strings::run();
}

 

 

 

strings.rs

// Primitive str = Immutable fixed-length string somewhere in memory
// String = Growable, heap-allocated data structure - Use when you need modify or own string data

pub fn run() {
    let mut hello = String::from("Hello ");

    //Get length
    println!("Length: {}", hello.len());

    // Push char
    hello.push('W');

    //  Push string
    hello.push_str("orld!");

    // Capacity in bytes
    println!("Capactity: {}", hello.capacity());

    // Check if empty
    println!("Is Empty: {}", hello.is_empty());
    // Contains
    println!("Contains 'World' {}", hello.contains("World"));

    // Replace
    println!("Replace: {}", hello.replace("World", "There"));

    // Loop through string by whitespace
    for word in hello.split_whitespace() {
        println!("{}", word);
    }

    // Create stirng with capacity
    let mut s = String::with_capacity(10);
    s.push('a');
    s.push('b');

    //Assertion testing
    assert_eq!(2, s.len());
    assert_eq!(10, s.capacity());
    println!("{}", s);
}

 

 

main.rs

// mod print;
// mod vars;
mod types;

fn main() {
    // print::run();
    // vars::run();
    types::run();
}

 

 

types.rs

/*
Primitive Type
Intergers: u8, i8, u16, i16, u32, i32, u64, i64, u128, i128(number of bits they take in memory)
Floats: f32, f64
Boolean (bool)
Characters(char)
Tuples
Arrays
*/

// Rust is a statically typed language, which means that it must know the types of all variable at compile time, however, the compiler can usually infer what type we want to use based on the value and how we use it.

pub fn run() {
    // Default is "i32"
    let x = 1;

    // Default is "f64"
    let y = 2.5;

    // Add explicit type
    let z: i64 = 454545455;

    // Find max size
    println!("Max i32: {}", std::i32::MAX);
    println!("Max i64: {}", std::i64::MAX);

    // Boolean
    let is_active: bool = true;

    // Get boolean from expression
    let is_greater: bool = 10 < 5;

    let a1 = 'a';
    let face = '\u{1F600}';

    println!("{:?}", (x, y, z, is_active, is_greater, a1, face));
}

 

 

 

 

 

 

 

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