added function and variable lessons.

the_book/branches/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "branches"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

the_book/branches/src/main.rs

@@ -0,0 +1,66 @@
+fn main() {
+    let condition = true;
+    let number = if condition { 5 } else { 6 };
+
+    if number % 4 == 0 {
+        println!("number is divisible by 4");
+    } else if number % 3 == 0 {
+        println!("number is divisible by 3");
+    } else if number % 2 == 0 {
+        println!("number is divisible by 2");
+    } else {
+        println!("number is not divisible by 4, 3, or 2");
+    }
+
+    //breaking out of multiple layers.
+    let mut count = 0;
+    'counting_up: loop {
+        println!("count = {}", count);
+        let mut remaining = 10;
+
+        loop {
+            println!("remaining = {}", remaining);
+            if remaining == 9 {
+                break;
+            }
+            if count == 2 {
+                break 'counting_up;
+            }
+            remaining -= 1;
+        }
+
+        count += 1;
+    }
+    println!("End count = {}", count);
+
+    //returning loop
+    let mut counter = 0;
+
+    let result = loop {
+        counter += 1;
+
+        if counter == 10 {
+            break counter * 2;
+        }
+    };
+
+    println!("The result is {}", result);
+
+    //while loop
+    let mut number = 3;
+
+    while number != 0 {
+        println!("{}!", number);
+
+        number -= 1;
+    }
+
+    println!("LIFTOFF!!!");
+
+    //for loop
+    let a = [10, 20, 30, 40, 50];
+
+    for element in a {
+        println!("the value is: {}", element);
+    }
+}

the_book/functions/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "functions"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

the_book/functions/src/main.rs

@@ -0,0 +1,16 @@
+fn main() {
+    another_function(5);
+    print_labeled_measurement(50, 'm');
+    println!("The returned value is {}", plus_one(4));
+}
+
+fn another_function(x: i32) {
+    println!("The value of x is: {}", x);
+}
+fn print_labeled_measurement(value: i32, unit_label: char) {
+    println!("The measurement is: {}{}", value, unit_label);
+}
+//adds one and returns
+fn plus_one(x:i32) -> i32 {
+    x+1
+}

the_book/variables/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "variables"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

the_book/variables/src/main.rs

@@ -0,0 +1,12 @@
+fn main() {
+    let x = 5;
+
+    let x = x + 1;
+
+    {
+        let x = x * 2;
+        println!("The value of x in the inner scope is: {}", x);
+    }
+
+    println!("The value of x is: {}", x);
+}