1 files changed, 12 insertions, 0 deletions
diff --git a/src/input.rs b/src/input.rs
index cc93415..ecb4b3f 100644
--- a/src/input.rs
+++ b/src/input.rs
@@ -15,6 +15,9 @@ impl Calculator {
                 KeyCode::Char('q') => {
                     return Signal::Exit;
                 }
+                KeyCode::Char('j' | 'k') => {
+                    self.swap();
+                }
                 KeyCode::Char(c) => {
                     self.push_to_buffer(c);
                 }
@@ -51,4 +54,13 @@ impl Calculator {
         self.stack.push(self.input_buffer.parse::<f64>().unwrap());
         self.input_buffer = String::new();
     }
+
+    fn swap(&mut self) {
+        if let Some(f) = self.stack.pop() {
+            if self.input_buffer.len() > 0 {
+                self.push_buffer_to_stack();
+            }
+            self.input_buffer = format!("{}", f);
+        }
+    }
 }