rename Data Structure -> data_structure (#644)

data_structure/Stack Using Linked List.cpp

@@ -0,0 +1,73 @@
+#include <iostream>
+using namespace std;
+
+struct node
+{
+	int val;
+	node *next;
+};
+
+node *top;
+
+void push(int x)
+{
+	node *n = new node;
+	n->val = x;
+	n->next = top;
+	top = n;
+}
+
+void pop()
+{
+	if (top == NULL)
+	{
+		cout << "\nUnderflow";
+	}
+	else
+	{
+		node *t = top;
+		cout << "\n"
+			 << t->val << " deleted";
+		top = top->next;
+		delete t;
+	}
+}
+
+void show()
+{
+	node *t = top;
+	while (t != NULL)
+	{
+		cout << t->val << "\n";
+		t = t->next;
+	}
+}
+
+int main()
+{
+	int ch, x;
+	do
+	{
+		cout << "\n1. Push";
+		cout << "\n2. Pop";
+		cout << "\n3. Print";
+		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();
+		}
+	} while (ch != 0);
+
+	return 0;
+}