From b9b930213fc2a2e7c86b335cc70099c45a6c24ea Mon Sep 17 00:00:00 2001
From: Krishna Vedala <krishna.vedala@ieee.org>
Date: Thu, 28 May 2020 16:05:43 -0400
Subject: [PATCH] use pointers instead of non-const references and globals

---
 others/tower_of_hanoi.cpp | 37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/others/tower_of_hanoi.cpp b/others/tower_of_hanoi.cpp
index d6c229617..323b2e424 100644
--- a/others/tower_of_hanoi.cpp
+++ b/others/tower_of_hanoi.cpp
@@ -13,21 +13,22 @@ struct tower {
     int values[10];
     //! top tower ID
     int top;
-} F, U, T;
+};
 
 /** Display the towers */
-void show() {
+void show(const struct tower *const F, const struct tower *const T,
+          const struct tower *const U) {
     std::cout << "\n\n\tF : ";
-    for (int i = 0; i < F.top; i++) {
-        std::cout << F.values[i] << "\t";
+    for (int i = 0; i < F->top; i++) {
+        std::cout << F->values[i] << "\t";
     }
     std::cout << "\n\tU : ";
-    for (int i = 0; i < U.top; i++) {
-        std::cout << U.values[i] << "\t";
+    for (int i = 0; i < U->top; i++) {
+        std::cout << U->values[i] << "\t";
     }
     std::cout << "\n\tT : ";
-    for (int i = 0; i < T.top; i++) {
-        std::cout << T.values[i] << "\t";
+    for (int i = 0; i < T->top; i++) {
+        std::cout << T->values[i] << "\t";
     }
 }
 
@@ -35,10 +36,10 @@ void show() {
  * \param [in,out] From tower to move disk *from*
  * \param [in,out] To  tower to move disk *to*
  */
-void mov(tower &From, tower &To) {
-    --From.top;
-    To.values[To.top] = From.values[From.top];
-    ++To.top;
+void mov(tower *From, tower *To) {
+    --From->top;
+    To->values[To->top] = From->values[From->top];
+    ++To->top;
 }
 
 /**
@@ -48,20 +49,22 @@ void mov(tower &From, tower &To) {
  * \param [in,out] Using temporary tower for the puzzle
  * \param [in,out] To  tower to move disk to
  */
-void TH(int n, tower &From, tower &Using, tower &To) {
+void TH(int n, tower *From, tower *Using, tower *To) {
     if (n == 1) {
         mov(From, To);
-        show();
+        show(From, To, Using);
     } else {
         TH(n - 1, From, To, Using);
         mov(From, To);
-        show();
+        show(From, To, Using);
         TH(n - 1, Using, From, To);
     }
 }
 
 /** Main function */
 int main() {
+    struct tower F, U, T;
+
     F.top = 0;
     U.top = 0;
     T.top = 0;
@@ -75,8 +78,8 @@ int main() {
         F.values[F.top++] = i;
     }
 
-    show();
-    TH(no, F, U, T);
+    show(&F, &T, &U);
+    TH(no, &F, &U, &T);
 
     return 0;
 }