5.conditional-expressions.md

Types of conditional expression:

• if expression
  • if expression

    if learn_language == "Rust" { 
       println!("You are learning Rust language!");
    }

  • if...else expression

    if learn_language == "Rust" { 
       println!("You are learning Rust language!");
    }
    else {
       println!("You are learning some other language!");
    } 

  • if...else if...else Expression

    if learn_language == "Rust" { 
       println!("You are learning Rust language!");
    } else if learn_language == "Java" { 
       println!("You are learning Java language!");
    } else {
       println!("You are learning some other language!");
    } 

  • ternary if-else Expression

   let res= if learn_language == "Rust" {"You are learning Rust language!"} else {"You are learning some other language!"};

• if let expression

   //todo

• match expression

    let x = 5;
    // define match expression
    match x {
          1 => println!("Java"),
          2 => println!("Python"),
          3 => println!("C++"),
          4 => println!("C#"),
          5 => println!("Rust"),
          6 => println!("Kotlin"),
          _ => println!("Some other value"),
    };
    let course = "Rust";
    // return value of match expression in a variable
    let found_course = match course {
        "Rust" => "Object/Functional",
        "Java" => "Object",
        "C++" => "Object",
        "C#" => "Object",
        _ => "Unknown Language"
    };

• advanced match

    let m = 10;
    match m {
        1..=3 => println!("a"),
        10 | 12 | 13 => println!("c"),
        15..=30 => println!("b"),
        _ => println!("default")
    }
    match m {
         n @ 1..=3 => println!("a with matched value {}", n),
         n @ 10 | 12 | 13 => println!("c  with matched value {}", n),
         n @ 15..=30 => println!("b  with matched value {}", n),
         _ => println!("default")
    }
    let matched_age = match m {
         n @ 1..=3 => 3,
         n @ 10 | 11 | 12 | 13 => 13,
         n @ 15..=30 => 30,
         _ => 100
    }        
    let tup = (1,2);
    match tup {
        (1, x) => println!("print value, {}",x), // x is 2
        (y, 2) => println!("print value, {}",y), // y is 1
        _ => println!("default")
    }
    match tup {
        (x, y) if x==y => println!("they are equal",x), 
        (x, y) if x+y==3 => println!("they have 3 as sum, {}",x+y),
        (x, _) if x%2==0 => println!("x is even number"), 
         _ => println!("default")
    }