added stack to folder

DSA/DSA-CPP/Stacks/implementingstackusingarray.cpp

@@ -0,0 +1,49 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Stack{
+    public:
+    int size;
+    int top;
+    int *arr;
+
+    int isempty(){
+        if(top==-1){
+            return 1;
+        }
+        return 0;
+    }
+    int isfull(){
+        if(top==size-1){
+            return 1;
+        }
+        return 0;
+    }
+};
+
+int main()
+{
+    // Stack s;
+    // s.size=80;
+    // s.top=-1;
+    // s.arr=new int[s.size];
+
+    Stack *s=new Stack;
+    s->size=4; 
+    s->top=-1;
+    s->arr=new int[s->size];
+
+    s->arr[++s->top]=4;
+    s->arr[++s->top]=5;
+    s->arr[++s->top]=8;
+    s->arr[++s->top]=9;
+
+    if(s->isempty()){
+        cout<<"The stack is empty";
+    }
+    else{
+        cout<<"The stack is not empty";
+    }
+
+    return 0;
+}