Black Horse programmer--"Dark Horse video note" OC Language Base code encapsulation

1. Note Points for encapsulation

   1:  //Member variable try not to use @public

   2:      //@public

   3:      int age;

   1:    //@public

   2:      //Read Only (readonly): Only allow outside access to my no, not allow the outside world to modify my no

   3:      int No;//Only a Get method is required

2.get, set method

   1:  Set method

   2:   1. Function: Provide a method to set the value of member variables to the outside world, can be in the method to face the parameters of the corresponding filter

   3:   2. Naming specification:

   4:   1> method name must start with set

   5:   2> set followed by the name of the member variable, the first letter of the member variable must be capitalized

   6:   3> return value must be void

   7:   4> must receive a parameter, and the parameter type is consistent with the member variable type

   8:   The name of the 5> parameter cannot be the same as the member variable name

   1:  Get method

   2:   1. Function: Returns the member variable inside the object

   3:   2. Naming specification:

   4:   1> must have a return value, the return value type must be the same as the member variable type

   5:   2> method name is the same as member variable name

   6:   3> does not need to receive any parameters

   1:  

   2:  //implementation of the Set method

   3:  -(void) Setage: (int) newage

   4:  {

   5:      //filter The parameters passed in

   6:      if (newage <= 0)

   7:      {

   8:          newage = 1;

   9:      }

  10:      

One   :  Age    = newage;

  :  }

  :  

  :  -(int) age

  :  {

  :      return age;

  :  }

3. Naming conventions for member variables:

Be sure to start with the following dash _

Role:

1. To separate the name of the member variable from the Get method
2. Can be separated from the local variables, a see the beginning of the underscore variable, is usually a member variable

Example

   1:  //The set and get methods for sex

   2:  -(void) Setsex: (Sex) sex;

   3:  -(sex) sex;

   4:  

   5:  //Set and get method for no

   6:  -(void) Setno: (int) No;

4. Practical examples of encapsulation

   1:  /*

   2:    4. Design a score class

   3:    * C language score (readable and writable)

   4:    * OC result (readable and writable)

   5:    * Total score (read only)

   6:    * Average score (read only)

   7:  * /

   8:  #import <Foundation/Foundation.h>

   9:  

  :  @Interface Score:nsobject

One   :  {

Int.   :      int//C language score

Int.   :      int//OC score

  14:      

  :      int _totalscore;  Total

  :      int//Average score

  :  }

  :  

  :  -(void) Setcscore: (int) Cscore;

  :  -(int) Cscore;

  £ º  

  :  -(void) Setocscore: (int) Ocscore;

At   :  -(int) Ocscore;

  :  

  :  -(int) Totalscore;

  :  -(int) Averagescore;

  :  

  :  @end

  £ º  

  :  @implementation Score

  :  -(void) Setcscore: (int) Cscore

  :  {

  :      _cscore = Cscore;

  34:      

  :      //Calculate total score

  £ º      _totalscore = _cscore + _ocscore;

  Panax notoginseng  :    _averagescoe = _TOTALSCORE/2;

  :  }

The   following  :-(int) Cscore

Max   :  {

A   :      return _cscore;

  :  }

  :  

  :  -(void) Setocscore: (int) Ocscore

  :  {

  :      _ocscore = Ocscore;

  47:      

Sum   :      //Calculate total score

  £      _totalscore = _cscore + _ocscore;

  :      _averagescoe = _TOTALSCORE/2;

  Wuyi:  }

  :  //change of listener member variable

  :  

Wu   :  -(int) Ocscore

  :  {

  £ º      return _ocscore;

  £ º  }

  :  

Totalscore   :  -(int)

  :  {

  :      return _totalscore;

+   :  }

Averagescore   :  -(int)

  :  {

  :      return _averagescoe;

  :  }

  :  @end

  :  

  :  

  :  int main ()

  :  {

  :      new];

  73:      

A   :      [s setcscore:90];

  :      [s setocscore:100];

  76:      

  :      [s setcscore:80];

  78:      

  79:      

n   :      int a = [s totalscore];

  81:      

  :      NSLog (@ "total:%d", a);

  83:      

+   :      return 0;

  :  }

Black Horse programmer--"Dark Horse video note" OC Language Base code encapsulation