10.structs.md

Structs

• Structs are similar to tuples in this regard. However, unlike tuples, you must define the data type of the item within the struct.

struct Course {
   code:i32,
   name:String,
   level:String, 
}

let mut course1 = Course  {
   name:String::from("Rust"),
   level:String::from("beginner"),
   code:130,
};
let course2 = Course  {
   name:String::from("Javascript"),
   level:String::from("beginner"),
   code:122,
};
//update
course1.name = "Java".to_string();
course1.code = 134;

• The name of the struct should be in PascalCase, meaning, the first letter of each word in a compound word is capitalized.

• If this case is not followed, a warning, ⚠️, is generated by the compiler.

• The order in which you assign values to items does not matter.

• A struct instance is immutable by default. Therefore it cannot be updated unless made mutable. However, the values can be accessed.

• Pass Structs to a function

fn display_mycourse_info(c:Course) {
    println!("Name:{}, Level:{} ,code: {}", c .name, c .level, c.code);
}

• return a struct from a function

fn return_rust_course_info(c1:Course, c2:Course)-> Course{
 //impl
}

Method of Structs

// citing to struct mentioned above `Course`
//impl construct to define struct methods
impl Course {
    fn name_code(&self) -> String {
        format!("{} {}", self.name, self.code)
    }
}

Related/Static method in structs

impl Course {
   // static method also called as related methods
   fn my_static_method(n: String, l: String, c:i32) -> Course {
      Course { 
      name: n, 
      level:l,
      code:c
       }
   } // such methods can be accessed using `::` operator. 
   //display
   fn display(&self){
      println!("name :{} code:{} of type: {}", self.name, self.code, self.level );
   }
}

Tuple Structs

//define a tuple struct
struct FruitQuantity(String, i32);
// main function
fn main() {
    // create an instance
    let r1 = FruitQuantity("oranges".to_string(), 12);
}

Print the value of struct using debug trait

#[derive(Debug)] // prints the value of struct using the debug trait
struct Point {
	x: i32,
	y: i32
}

Unions in Rust