Regx Validation in IOS

Email validation using Regx in iOS

+(BOOL) isValidEmail:(NSString *)email

{

    NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";

    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];

    return [emailTest evaluateWithObject:email];

}

Phone number validation using Regx in iOS

+(BOOL) isValidPhone:(NSString *)phone

{

    NSString *phoneRegex = @"[235689][0-9]{6}([0-9]{3})?";

    NSPredicate *test = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", phoneRegex];

    return [test evaluateWithObject:phone];

}

Password validation using Regx in iOS

+(BOOL) isPasswordValid:(NSString *)pwd

{

    if ( [pwd length]<6 || [pwd length]>32 ) return NO;  // too long or too short

    NSRange rang;

    rang = [pwd rangeOfCharacterFromSet:[NSCharacterSet letterCharacterSet]];

    if ( !rang.length ) return NO;  // no letter

    rang = [pwd rangeOfCharacterFromSet:[NSCharacterSet decimalDigitCharacterSet]];

    if ( !rang.length )  return NO;  // no number;

    return YES;

}

get device Name and device id in iOS 5 and IOS6 and iOS 7

#pragma mark - get unique id

 + (NSString *)getUUID

{

    return [[[UIDevice currentDevice] identifierForVendor] UUIDString];

}

#pragma  mark - get device name

 + (NSString *)getDeviceName

{

    return [[UIDevice currentDevice] name];

}

Different Label for Navigationbar title and back button

self.navigationItem.title=@"Recent Books";
UIBarButtonItem *backButton = [[UIBarButtonItem alloc]
                                   initWithTitle:@"Back"
                                   style:UIBarButtonItemStylePlain
                                   target:nil
                                   action:nil];
self.navigationItem.backBarButtonItem=backButton;

How to create back button in navigation bar

Add the following in viewWillappear

     UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:@"Back" style: UIBarButtonItemStyleBordered target:self action:@selector(Back)];
     self.navigationItem.leftBarButtonItem = backButton;

And in

- (IBAction)Back
  {
    [self dismissViewControllerAnimated:YES completion:nil]; // ios 6
  }

IOS gradient Button

// Add Border to button
        CALayer *layer = btnCalender.layer;
        layer.cornerRadius = 5.0f;
        layer.masksToBounds = YES;
        layer.borderWidth = 1.0f;
        layer.borderColor = [UIColor colorWithWhite:0.3f alpha:0.2f].CGColor;
        
        // Add Shine to button
        CAGradientLayer *Layer = [CAGradientLayer layer];
        Layer = layer.bounds;
        Layer.colors = [NSArray arrayWithObjects:
                             (id)[UIColor colorWithWhite:1.0f alpha:0.4f].CGColor,
                             (id)[UIColor colorWithWhite:1.0f alpha:0.2f].CGColor,
                             (id)[UIColor colorWithWhite:0.75f alpha:0.2f].CGColor,
                             (id)[UIColor colorWithWhite:0.4f alpha:0.2f].CGColor,
                             (id)[UIColor colorWithWhite:1.0f alpha:0.4f].CGColor,
                             nil];
        Layer.locations = [NSArray arrayWithObjects:
                                [NSNumber numberWithFloat:0.0f],
                                [NSNumber numberWithFloat:0.2f],
                                [NSNumber numberWithFloat:0.3f],
                                [NSNumber numberWithFloat:0.0f],
                                [NSNumber numberWithFloat:1.0f],
                                nil];
        [layer addSublayer: Layer];

using a unique identifier of iPhone or iOS device

Create a UUID: A string containing a UUID. The standard format for UUIDs represented in ASCII is a string punctuated by hyphens, for example 68753A44-4D6F-1226-9C60-0050E4C00067.

+ (NSString *)newUUID
{
    CFUUIDRef theUUID = CFUUIDCreate(NULL);
    CFStringRef string = CFUUIDCreateString(NULL, theUUID);
    CFRelease(theUUID);
    return (NSString *)string;
}

Check for internet connection

Please Use Any Of the below Code

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(networkChanged:) name:kReachabilityChangedNotification object:nil];

reachability = [Reachability reachabilityForInternetConnection];
[reachability startNotifier];

- (void)networkChanged:(NSNotification *)notification
{

  NetworkStatus remoteHostStatus = [reachability currentReachabilityStatus];

  if(remoteHostStatus == NotReachable) { NSLog(@"not reachable");}
  else if (remoteHostStatus == ReachableViaWiFiNetwork) { NSLog(@"wifi"); }
  else if (remoteHostStatus == ReachableViaCarrierDataNetwork) { NSLog(@"carrier"); }
}

Or

#import <CoreFoundation/CoreFoundation.h>
#import <SystemConfiguration/SystemConfiguration.h>
#import <netdb.h>

BOOL networkReachable()
{
    struct sockaddr_in zeroAddress;
    bzero(&zeroAddress, sizeof(zeroAddress));
    zeroAddress.sin_len = sizeof(zeroAddress);
    zeroAddress.sin_family = AF_INET;

    SCNetworkReachabilityRef reachabilityRef = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr *) &zeroAddress);

    SCNetworkReachabilityFlags flags;
    if (SCNetworkReachabilityGetFlags(reachabilityRef, &flags)) {
        if ((flags & kSCNetworkReachabilityFlagsReachable) == 0) {
            // if target host is not reachable
            return NO;
        }

        if ((flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0) {
            // if target host is reachable and no connection is required
            //  then we'll assume (for now) that your on Wi-Fi
            return YES; // This is a wifi connection.
        }


        if ((((flags & kSCNetworkReachabilityFlagsConnectionOnDemand ) != 0)
            ||(flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) != 0)) {
            // ... and the connection is on-demand (or on-traffic) if the
            //     calling application is using the CFSocketStream or higher APIs

            if ((flags & kSCNetworkReachabilityFlagsInterventionRequired) == 0) {
                // ... and no [user] intervention is needed
                return YES; // This is a wifi connection.
            }
        }

        if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN) {
            // ... but WWAN connections are OK if the calling application
            //     is using the CFNetwork (CFSocketStream?) APIs.
            return YES; // This is a cellular connection.
        }
    }

    return NO;
}

or

- (BOOL)connectedToInternet

{
   NSURL *url=[NSURL URLWithString:@"http://www.google.com"];
   NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:url];
   [request setHTTPMethod:@"HEAD"];
   NSHTTPURLResponse *response;
   [NSURLConnection sendSynchronousRequest:request returningResponse:&response error: NULL];

   return ([response statusCode]==200)?YES:NO;
}

Virtual Function in C++ Programming

                             If there are member function with same name in derived classes, virtual functions gives programmer capability to call member function of different class by a same function call depending upon different context. This feature in C++ programming is known as polymorphism which is one of the important feature of OOP.

Example
#include <stdio.h>
  using namespace std; 
   class B { 
       public: 
           void display() {
                  cout<<"Content of base class.\n"; 
               }
 }; 
class D : public B {

 public:   
 void display() {
      cout<<"Content of derived class.\n"; 
      }
 };
 int main() { 

B *b; 
D d;
 b->display(); 
b = &d; /* Address of object d in pointer variable */ 
b->display(); 
return 0; 
}

Output 
Content of base class. 
Content of base class. 

If you want to execute the member function of derived class then, you can declare display( ) in the base class virtual which makes that function existing in appearance only but, you can't call that function. In order to make a function virtual, you have to add keyword virtual in front of a function. 

* Example to demonstrate the working of virtual function in C++ programming. */

#include <iostream>
using namespace std;
class B
{
    public:
     virtual void display()      /* Virtual function */
         { cout<<"Content of base class.\n"; }
};

class D1 : public B
{
    public:
       void display()
         { cout<<"Content of first derived class.\n"; }
};

class D2 : public B
{
    public:
       void display()
         { cout<<"Content of second derived class.\n"; }
};

int main()
{
    B *b;
    D1 d1;
    D2 d2;

/* b->display();  // You cannot use this code here because the function of base class is virtual. */

    b = &d1;
    b->display();   /* calls display() of class derived D1 */
    b = &d2;           
    b->display();   /* calls display() of class derived D2 */
    return 0;
}

Output

-------------

Content of first derived class.
Content of second derived class.

Inheritance in C++

What to inherit?
• In principle, every member of a base class is inherited by a derived class 
– just with different access permission

A class can be derived from more than one classes, which means it can inherit data and functions from multiple base classes. To define a derived class, we use a class derivation list to specify the base class(es). A class derivation list names one or more base classes and has the form:

class derived-class: access-specifier base-class

Access Control Over the Members
• Two levels of access control over class members
– class definition – inheritance type

base class/ superclass/ parent class

class Point{
protected: int x, y;
public: void set(int a, int b);
};

derived class/ subclass/ child class

class Circle : public Point{ ......
};

0 

Example 

// derived classes
#include <iostream>
using namespace std;

class CPolygon {
  protected:
    int width, height;
  public:
    void set_values (int a, int b)
      { width=a; height=b;}
  };

class CRectangle: public CPolygon {
  public:
    int area ()
      { return (width * height); }
  };

class CTriangle: public CPolygon {
  public:
    int area ()
      { return (width * height / 2); }
  };
  
int main () {
  CRectangle rect;
  CTriangle trgl;
  rect.set_values (4,5);
  trgl.set_values (4,5);
  cout << rect.area() << endl;
  cout << trgl.area() << endl;
  return 0;
}

Friend classes

In principle, private and protected members of a class cannot be accessed from outside the same class in which they are declared. However, this rule does not affect friends.

Friends are functions or classes declared with the friend keyword.
A class as friend of another one, granting that first class access to the protected and private members of the second one.

/ friend class
#include <iostream>

class CSquare;

class CRectangle {
    int width, height;
  public:
    int area ()
      {return (width * height);}
    void convert (CSquare a);
};

class CSquare {
  private:
    int side;
  public:
    void set_side (int a)
      {side=a;}
    friend class CRectangle;
};

void CRectangle::convert (CSquare a) {
  width = a.side;
  height = a.side;
}
  
int main () {
  CSquare sqr;
  CRectangle rect;
  sqr.set_side(4);
  rect.convert(sqr);
  cout << rect.area();
  return 0;
}

Friend functions

Private and protected members of a class cannot be accessed from outside the same class in which they are declared. However, this rule does not affect friends,

A friend function of a class is defined outside that class' scope but it has the right to access all private and protected members of the class. Even though the prototypes for friend functions appear in the class definition, friends are not member functions.

Friends are functions or classes declared with the friend keyword.
                          If we want to declare an external function as friend of a class, thus allowing this function to have access to the private and protected members of this class, we do it by declaring a prototype of this external function within the class, and preceding it with the keyword friend: 

#include <iostream>
 
 
class Student
{
   double id;
public:
   friend void printid( Student Student );
   void setId( double wid );
};

// Member function definition
void  Student ::setId( double wid )
{
    id = wid;
}

// Note: printId() is not a member function of any class.
void printId(  Student  student )
{
   /* Because setid() is a friend of Student, it can
    directly access any member of this class */
   cout << "Id of student : " << student .id <<endl;
}
 
// Main function for the program
int main( )
{
    Student  student ;
 
   // set student id without member function
   student .setId(10.0);
   
   // Use friend function to print the wdith.
   printId( student );
 
   return 0;
}