nie-ii-year

commit 5411f4b69440ffe0e10df0c5d120914044a76bd9
parent 67f13e3e3b2a6c7914f7083a5775e7bcf7bf6ec1
Author: Agastya Chandrakant <acagastya@outlook.com>
Date:   Fri, 27 Oct 2017 00:38:17 +0530

More cloning material
Diffstat:
A
s3/oops/stack.cpp
 | 
101
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 101 insertions(+), 0 deletions(-)
diff --git a/s3/oops/stack.cpp b/s3/oops/stack.cpp
@@ -0,0 +1,101 @@
+#include <iostream>
+using namespace std;
+class node{
+  int data;
+  node* next;
+public:
+  node(int data){
+    this->next = NULL;
+    this->data = data;
+  };
+  node* prepend(node* h){
+    this->next = h;
+    return this;
+  };
+  node* oldElementBecomesHead(){
+    return this->next;
+  };
+  int getCurrentValue(){
+    return this->data;
+  }
+};
+
+bool isNULL(node*h){
+  if(h == NULL)
+    return true;
+  return false;
+}
+
+class stack {
+  node* head;
+  int input;
+public:
+  stack(){
+    head = NULL;
+  };
+  friend bool isNULL(node*);
+  void operator+(int input){
+    node* temp = new node(input);
+    if(isNULL(temp)){
+      std::cout << "Insufficient memory." << std::endl;
+      return;
+    }
+    else {
+      if(isNULL(head) == true)
+        head = temp;
+      else
+        head = temp->prepend(head);
+    }
+  };
+  void operator-(){
+    if(isNULL(head))
+      std::cout << "Stack underflow." << std::endl;
+    else{
+      node *temp = head;
+      head = head->oldElementBecomesHead();
+      std::cout << temp->getCurrentValue() << " has been popped." << std::endl;
+      delete temp;
+    }
+  };
+  void display(){
+    node* temp = head;
+    if(isNULL(temp)){
+      std::cout << "Stack is empty." << std::endl;
+      return;
+    }
+    else{
+      while (temp != NULL) {
+        std::cout << temp->getCurrentValue() << " ";
+        temp = temp->oldElementBecomesHead();
+      }
+      std::cout << std::endl;
+    }
+  };
+};
+
+int main() {
+  stack s;
+  int choice, input;
+  do{
+    std::cout << "1. Push 2. Pop 3. Display 4. Quit\nYour choice> ";
+    std::cin >> choice;
+    switch (choice) {
+      case 1:
+              std::cout << "Enter an element to be pushed: ";
+              std::cin >> input;
+              s + input;
+              break;
+      case 2:
+              -s;
+              break;
+      case 3:
+               s.display();
+              break;
+      case 4:
+              choice = 0;
+              break;
+      default: std::cout << "Invalid choice, try again." << std::endl;
+    }
+  }while(choice);
+  return 0;
+}