ch5 methods almost complete

rectangles/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "rectangles"
+version = "0.1.0"

rectangles/Cargo.toml

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+[package]
+name = "rectangles"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

rectangles/src/main.rs

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+fn main() {
+    // main_with_tuple();
+    main_with_struct();
+    // two values are unrelated in the code, only by name
+    // let length1 = 8;
+    // let width1 = 4;
+
+    // println!("The area of a rectangle is {} square units.",
+    // area(length1, width1)
+    // )
+}
+
+fn area (length: i32, width: i32) -> i32 {
+    length * width
+}
+
+fn main_with_tuple () {
+    // vaules are related now but no distinction between length and width
+    // less clear, would have to remember that the first value is the length and second is width if used anywhere else such as drawing to the screen
+    let rectangle1 = (8, 4);
+    println!("The area of a rectangle is {} square units.",
+    area_with_tuple(rectangle1)
+    );
+}
+
+// only needs one argument
+fn area_with_tuple (dimensions: (i32, i32)) -> i32 {
+    // much less clear what is going on here, names only help a bit
+    dimensions.0 * dimensions.1
+}
+
+struct Rectangle {
+    // negative length/width shapes dont exist
+    length: u32,
+    width: u32,
+}
+fn main_with_struct () {
+    // clearly defined what is going on without the need of comments
+    let rect1 = Rectangle {
+        length: 8,
+        width: 4,
+    };
+    println!("The area of a rectangle is {} square units.",
+    area_with_struct(&rect1)
+    );
+}
+
+// prefer to borrow a struct rather than own
+fn area_with_struct (rect: &Rectangle) -> u32 {
+    // way mroe clear the relationship between the two values
+    rect.length * rect.width
+}