ece150: add sorting

docs/ce1/ece150.md

@@ -339,4 +339,44 @@ Pointers to `const` values must also be `const`.
     int const *p_x{&x};
     ```
     
+## Sorting algorithms
 
+### Selection sort
+
+Selection sort takes the largest item in the array each time and adds it to the end.
+
+```rust
+fn selection_sort(array: &mut [i32]) {
+    for i in (0..array.len()).rev() {
+        let mut max_index = 0;
+        for j in 0..i + 1 {
+            if array[j] > array[max_index] {
+                max_index = j;
+            }
+        }
+        let _ = &array.swap(i, max_index);
+    }
+}
+```
+
+### Insertion sort
+
+Insertion sort assumes the first element of the array is sorted and expands that partition by moving each element afterward to the correct spot.
+
+```rust
+fn insertion_sort(array: &mut [i32]) {
+    for i in 1..array.len() {
+        let mut temp = array[0];
+        for j in 0..i {
+            if array[j] < array[i] {
+                temp = array[i];
+                for k in (j..i).rev() {
+                    array[k + 1] = array[k]
+                }
+                array[j] = temp;
+                break;
+            }
+        }
+    }
+}
+```