You can approximate π by using the following formulas: pi += sign / (2 * i - 1.0); where i is the name of a variable in a for loop and pi is the name of the variable for π and sign has an initial value of 1 when it is declared and within the for loop is set to equal the negative of itself. Make sure you use a for loop for this assignment. The for loop's starting value should be 2 and ending value should be when i is less than or equal to 100000. If the value of Write a Windows application that gets names and e-mail addresses from the user and displays a list of all of the user's contacts. Each time the user enters a new contact, he/she should able to see it added to a list of previously stored contacts. For example, in the following sample output below, after the user clicks the "Add Contact" button, the list will include John Mann's contact information at the bottom.