Added dynamic stack using array and template

Data Structures/Stacks/dynamic_stack/README.md

@@ -0,0 +1,71 @@
+# Dynamic Stack using Array
+
+The idea of a dynamic stack is to allocate additional memory so that the "stack full" scenario does not occur frequently.
+By allocating new memory that is bigger than the existing stack memory and copying elements from the old stack to the new stack, a Growable array-based Stack may be created. 
+
+## Templates
+
+The basic concept is to give the data type as a parameter, eliminating the need to write the same code for multiple data types. A software firm, for example, may require sort() for several data type. We can build a single sort() function and give data type as a parameter instead of creating and maintaining several codes.
+
+## Operations
+
+`size():`
+
+```
+return nextIndex;
+```
+
+`checkEmpty():`
+
+```
+return nextIndex==0;        
+```
+
+`push(x):`
+
+```
+if(nextIndex==capacity){
+T *newdata=new T[capacity*2];
+for(int i=0;i<capacity;i++){
+newdata[i]=data[i];
+}
+capacity*=2;
+delete []data;
+data=newdata;                   
+}        
+data[nextIndex]=element;
+nextIndex++;
+```
+
+`pop():`
+
+```
+if(checkEmpty()){
+cout<<"stack is empty"<<endl;
+return 0;
+}
+nextIndex--;
+return data[nextIndex];
+```  
+
+`top():`
+
+```
+ return data[nextIndex-1];
+```
+
+## Errors:
+
+- Underflow: An attempt was made to pop an empty stack.
+
+## Applications:
+
+- Expression evaluation.
+- Check parenthesis matching in an expression.
+- Conversion from one form of expression to another.
+- Memory Management.
+- Backtracking problems.
+
+
+
+

Data Structures/Stacks/dynamic_stack/dynamic_stacks_using_array_and_template.cpp

@@ -0,0 +1,121 @@
+#include <iostream>
+using namespace std;
+template<typename T> //template
+class StackUsingArray{
+    T *data;
+    int nextIndex;
+    int capacity;
+
+public:
+    StackUsingArray(){
+    data= new T[4];
+    nextIndex=0;
+    capacity=4;
+    }
+
+    int size(){
+        return nextIndex;
+    }
+
+    bool checkEmpty(){
+        return nextIndex==0;        
+    }
+
+    void push(T element){
+        if(nextIndex==capacity){
+        T *newdata=new T[capacity*2];   //dynamic_stack
+        for(int i=0;i<capacity;i++){
+            newdata[i]=data[i];
+        }
+        capacity*=2;
+        delete []data;
+        data=newdata;
+
+
+        }
+
+       data[nextIndex]=element;
+       nextIndex++;
+
+    }
+
+    int pop(){
+        if(checkEmpty()){
+            cout<<"stack is empty"<<endl;
+            return 0;
+        }
+        nextIndex--;
+    return data[nextIndex];
+    }
+
+    int top(){
+        return data[nextIndex-1];
+    }
+
+    void display(){
+        for(int i=0;i<nextIndex;i++){
+            cout<<data[i]<<endl;
+        }
+    }
+};
+
+int main(){
+    StackUsingArray<int> s;       
+    int ch;
+
+     while(ch!=7)
+    {
+        cout<<"\n1. Push\n";
+        cout<<"2. Pop\n";
+        cout<<"3. top\n";
+        cout<<"4. size\n";
+        cout<<"5. check\n";
+        cout<<"6. display\n";
+        cout<<"\nEnter your Choice :: ";
+        cin>>ch;
+
+        switch(ch)
+        {
+            case 1:
+            int x;
+            cout<<"enter the element"<<endl;
+            cin>>x;
+                s.push(x);
+                break;
+
+            case 2:
+                s.pop();
+                break;
+
+            case 3:
+                cout<<s.top()<<endl;
+                break;
+
+            case 4:
+
+                s.size();
+
+                break;
+
+                case 5:
+                s.checkEmpty();
+                break;
+
+                case 6:
+                s.display();
+                break;
+
+                case 7:
+                ch=7;
+                cout<<"\nPress any key .. ";
+                break;
+
+            default:
+                cout<<"\nWrong Choice!! \n";
+                break;
+        }
+    }
+
+
+    return 0;
+}

README.md

@@ -8,6 +8,7 @@ A curated list of [Data Structres](Data%20Structures) and [Algorithms](Algorithm
     - [Doubly Linked List](Data%20Structures/Linked%20List/DoublyLinkedList.cpp)
 - [Stacks](Data%20Structures/Stacks)
     - [Array Implementation](Data%20Structures/Stacks/Stacks_ArrayImplementation.cpp)
+    - [Dynamic Stack using Array and Template](Data%20Structures/Stacks/dynamic_stack/dynamic_stacks_using_array_and_template.cpp)
     - [Linked List Implementation](Data%20Structures/Stacks/Stacks_LLImplementation.cpp)
 - [Queues](Data%20Structures/Queues)
     - [Array Implementation](Data%20Structures/Queues/Queue_Array-Imp.cpp)