How to launch 'custom app' from xcode

[dustin.weeks]

Hello,

I am writing two programs <program-1> and <program-2>

now from <program-1> when user clicks a button i want to launch <program-2> how can i do it?

also if [UIapplication sharedApplication] openURL
also how to launch 'contacts book' using openURL?

Thanks,
Dustin.

[jnic]

Custom URL schemes. (http://iphonedevelopertips.com/cocoa/launching-your-own-application-via-a-custom-url-scheme.html)

also how to launch 'contacts book' using openURL?

Not supported. (https://developer.apple.com/iphone/library/featuredarticles/iPhoneURLScheme_Reference/Introduction/Introduction.html)