rename Data Structure -> data_structure (#644)

data_structure/Stack Using Array.cpp

@@ -0,0 +1,79 @@
+#include <iostream>
+using namespace std;
+
+int *stack;
+int top = 0, size;
+
+void push(int x)
+{
+	if (top == size)
+	{
+		cout << "\nOverflow";
+	}
+	else
+	{
+		stack[top++] = x;
+	}
+}
+
+void pop()
+{
+	if (top == 0)
+	{
+		cout << "\nUnderflow";
+	}
+	else
+	{
+		cout << "\n"
+			 << stack[--top] << " deleted";
+	}
+}
+
+void show()
+{
+	for (int i = 0; i < top; i++)
+	{
+		cout << stack[i] << "\n";
+	}
+}
+
+void topmost()
+{
+	cout << "\nTopmost element: " << stack[top - 1];
+}
+int main()
+{
+	cout << "\nEnter Size of stack : ";
+	cin >> size;
+	stack = new int[size];
+	int ch, x;
+	do
+	{
+		cout << "\n1. Push";
+		cout << "\n2. Pop";
+		cout << "\n3. Print";
+		cout << "\n4. Print topmost element:";
+		cout << "\nEnter Your Choice : ";
+		cin >> ch;
+		if (ch == 1)
+		{
+			cout << "\nInsert : ";
+			cin >> x;
+			push(x);
+		}
+		else if (ch == 2)
+		{
+			pop();
+		}
+		else if (ch == 3)
+		{
+			show();
+		}
+		else if (ch == 4)
+		{
+			topmost();
+		}
+	} while (ch != 0);
+
+	return 0;
+}