matrices and transposing. Also compiling dead code

src/main.rs

@@ -1,14 +1,40 @@
-fn main() {
-    let a: [i32; 3] = [1, 2, 3];
-    let x: i8 = 15;
-    let y: i16 = 1000;
+// TODO
+#![allow(unused_variables, dead_code)]
 
-    for i in a {
-        println!("{}", i);
-        println!("i * x * y = {}", multiply(i.into(), x.into(), y.into()));
+fn interesting() -> i32 {
+    // this code compiles and doesn't complain about being unused or not returning the correct
+    // thing, but will hit a runtime error if/when this is called
+    unimplemented!();
+}
+
+fn transpose(matrix: [[i32; 3]; 3]) -> [[i32; 3]; 3] {
+    let matrix_new = [
+        [matrix[0][0], matrix[1][0], matrix[2][0]], // newline
+        [matrix[0][1], matrix[1][1], matrix[2][1]],
+        [matrix[0][2], matrix[1][2], matrix[2][2]],
+    ];
+    return matrix_new;
+}
+
+fn pretty_print(matrix: &[[i32; 3]; 3]) {
+    println!("[");
+    for row in matrix {
+        println!("  [ {} {} {} ]", row[0], row[1], row[2]);
     }
+    println!("]");
 }
 
-fn multiply(a: i32, x: i32, y: i32) -> i32 {
-    return a * x * y;
+fn main() {
+    let matrix = [
+        [101, 102, 103], // we want the newline here
+        [201, 202, 203],
+        [301, 302, 303],
+    ];
+
+    println!("matrix:");
+    pretty_print(&matrix);
+
+    let transposed = transpose(matrix);
+    println!("transposed:");
+    pretty_print(&transposed);
 }