Beginner Guide iOS 5 Development : UIAlertView

UIAlertView *welcomemessage =[[UIAlertView alloc] initWithTitle:@"Wellcome" message:@"This is you first Alert Apps" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
[welcomemessage show];

- (void)viewDidLoad
{
    UIAlertView *welcomemessage =[[UIAlertView alloc] initWithTitle:@"Wellcome" message:@"This is you first Alert Apps" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
    [welcomemessage show];
    [super viewDidLoad];
}

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController
-(IBAction)Alert_Command:(id)sender;
@end

-(IBAction)Alert_Command:(id)sender{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Alert Message!" message:@"This is" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:@"1",@"2",@"3", nil];
    [alert show];
}

-(void) alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
    if(buttonIndex == 1){
        self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"1.jpeg"]];
    }
    if(buttonIndex == 2){
        self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"2.jpeg"]];
    }
    if(buttonIndex == 3){
        self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"3.jpeg"]];
    }
}

-(void) alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{    
    switch (buttonIndex) {
        case 0:
            self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"1.jpeg"]];
            break;
        case 1:
            self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"2.jpeg"]];
            break;
        case 2:
            self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"3.jpeg"]];
            break;
    }
}