functions, loops and control flow

functions/src/main.rs

@@ -0,0 +1,71 @@
+// fn main() {
+//     print_labelled_measurements(5, 'h');
+// }
+//
+// fn print_labelled_measurements(value: i32, unit_label: char) {
+//     println!("The measurement is: {value}{unit_label}");
+// }
+//
+// // a variable
+//
+use std::io::{self};
+
+fn main() {
+    println!(
+        "welcome to our rudimentary calculator!\nwe can do two things:\n1.factorial.2.square\nwhich one do you want?\n\t"
+    );
+    loop {
+        let mut input = String::new();
+
+        io::stdin()
+            .read_line(&mut input)
+            .expect("couldn't read line!");
+
+        let input: i32 = input.trim().parse().expect("numbers only");
+
+        if input > 2 || input < 0 {
+            println!("aye choose from the options foo");
+            break;
+        }
+
+        println!("\nalright and what number to operate on?\n\t");
+
+        let mut number = String::new();
+
+        io::stdin()
+            .read_line(&mut number)
+            .expect("couldn't read line!");
+
+        let number: i32 = number
+            .trim()
+            .parse()
+            .expect("aye foo enter a numberrr quit playin");
+
+        if input == 1 {
+            println!("\nthe factorial of {number} is {}", factorial(number));
+            break;
+        } else {
+            println!("\nthe square of {number} is {}", square(number));
+            break;
+        }
+    }
+
+    fn square(x: i32) -> i32 {
+        return x * x;
+    }
+
+    //TODO: fix factorial function after you figure out loops
+    //NOTE: we have implemented factorial in the the loops sub-directory
+    fn factorial(x: i32) -> i32 {
+        let mut rev = x - 1;
+        let mut result = x;
+        loop {
+            result *= rev;
+            rev -= 1;
+
+            if rev < 3 {
+                break result * 2;
+            }
+        }
+    }
+}