chore(CPlusPlus): add stack using array (#349)

algorithms/CPlusPlus/README.md

@@ -15,7 +15,6 @@
 1. [Bellman Ford Algorithm](Graphs/bellmam-ford.cpp)
 2. [kruskal Algorithm](Graphs/kruskal-algorithm.cpp)
 
-
 ## Multiplication
 1. [Karatsuba](Multiplication/karatsuba.cpp)
 
@@ -37,6 +36,7 @@
 
 ## Stacks
 1. [Balancing Parenthesis](Stacks/balanced-parenthesis.cpp)
+2. [Stack using Array](Stacks/stack-using-array.cpp)
 
 ## Sorting
 1. [Bubble Sort](Sorting/bubble-sort.cpp)

algorithms/CPlusPlus/Stacks/stack-using-array.cpp

@@ -0,0 +1,137 @@
+/* Program to implement stack using array */
+#include<iostream>
+using namespace std;
+class Stack
+{
+    int cur ,capacity ,*arr;
+public:
+    // constructor which takes capacity as argument
+    Stack(int capacity)
+    {
+        this->capacity = capacity;
+        cur = -1;
+        // dynamically allocating memory
+        arr=new int[capacity];
+        // if arr contain null
+        if(arr == NULL)
+        {
+            cout << "Memory not located";
+            exit(0);
+        }
+    }
+    ~Stack()
+    {
+        delete []arr;
+    }
+    void push(int);
+    void pop();
+    int top();
+    int empty();
+};
+// function to push data into stack
+void Stack::push(int data)
+{
+    if(cur == capacity-1)
+        cout << "Stack is full";
+    else
+    {
+    cur++;
+    arr[cur] = data;
+    }
+}
+// function to pop data from stack
+void Stack::pop()
+{
+    cur--;
+}
+// function to get the top most element of the stack
+int Stack::top()
+{
+    return arr[cur];
+
+}
+// function to check whether the stack is empty of not
+int Stack::empty()
+{
+    if(cur == -1)
+        return 1;
+    else
+        return 0;
+}
+// function to clear screen
+void clear_screen()
+{
+    #ifdef _WIN32
+        system("cls");
+    #elif __unix__
+        system("clear");
+    #else
+        cout << "clear screen not supports";
+    #endif
+}
+//driver code
+int main()
+{
+    int cap;
+    int choice ,data;
+    cout << "Enter the size: ";
+    cin >> cap;
+    Stack s(cap);
+    while(1)
+    {
+        cout << "1: Push\n2: Pop\n3: Top\n4:Exit\n\nEnter your choice ";
+        cin >> choice;
+        switch(choice)
+        {
+            // push data into stack
+        case 1:
+            cout << "Enter element: ";
+            cin >> data;
+            s.push(data);
+            break;
+        case 2:
+            // pop data from stack
+            if(s.empty())
+                cout << "Stack is empty";
+            else
+            {
+            data = s.top();
+            s.pop();
+            cout << "Popped element: " << data;
+            }
+            break;
+            // get top element from stack
+        case 3:
+            if(!s.empty())
+            {
+            data = s.top();
+            cout << "Top element: "<< data;
+            }
+            else
+                cout << "Stack is empty";
+            break;
+        case 4:
+            // exit
+            exit(0);
+        default:
+            // run default case when none one the above case runs
+            cout << "Invalid choice";
+        }
+        // clear the screen
+        clear_screen();
+    }
+}
+/*
+Input: Enter the size: 5
+Push -1
+Push 2
+Push 3
+Output:
+Pop 3
+Top 2
+Pop 2
+Pop -1
+Pop Stack is empty
+
+Time complexity: O(1) for all push,pop,top,empty
+*/