title: alert once on launch of iPhone/iPad application
body: <p>I want to popup an alert with "OK" and "Cancel" button.
  This alert should appear only once on first launch of iPhone/iPad application and for the alert if OK button is pressed then next launch of application the alert should not appear.
  If Cancel button is pressed then on the next launches of the application same alert should appear.</p>
  
  <p>My approach is to take any integer variable for which default value should be 0, when first time the application is launched this integer value should be checked if it is 0 only the alert should appear either no alert. If alert appears and the OK button is pressed, value should be changed to 1 and on the next launch of the application this integer value should be retained 1 so that the alert should not appear again.</p>
  
  <p>Please help what should be the type of this variable and how to retain the value on next launch of the application.</p>