3.Talk time calculation system. User will:
a.Input the balance
b.Select the type (postpaid/prepaid)
c.Select the operator
d.Click ‘calculate’ button
e.Talk time will be shown in a label.

4.Input any number from user and show the sum up
to that number.

5.show the following figure in a listbox/listview
where user inputs the level number of the triangle.
*
**
***
****
*****

6.There is a combobox showing product and products
price is the value type of that combobox. User will-

a.Select an item from the list
b.Input the number of product that he wants to buy
c.Click the add button
d.Product will be added in a gridview with product name,
unit price, item price
e.Current total amount will be shown outside of the gridview
f.If user clicks on a Save button, all of the items
in the gridview will be cleared.The items will be
updated into the appropriate item position in the gridview

7.this is the extension of the problem no.6
a.Add a Delete button into the datagridview.
b.If user clicks on the delete button, the whole row
will be deleted.