C++ Tutorial/Class/member method — различия между версиями

Текущая версия на 10:29, 25 мая 2010

Содержание

1 Declare a class with method
2 Default values in member functions
3 Implement class member function
4 member function overloading.
5 Overloading class member functions
6 overloading functions in base and derived classes
7 overloading two class member functions
8 The class member access operators . and ->
9 Use class as the member function parameter type

Declare a class with method

class ThreeDimension {  
public: 
  int X; 
  int Y;    
  int Z;        
 
  int range();   // compute and return the range 
};

Default values in member functions

#include <iostream>
 
 
 class Rectangle
 {
 public:
 
     Rectangle(int width, int height);
     ~Rectangle(){}
     void display(int aWidth, int aHeight, 
     bool UseCurrentVals = false) const;
 private:
     int itsWidth;
     int itsHeight;
 };
 
 
 Rectangle::Rectangle(int width, int height): itsWidth(width), itsHeight(height
) {}                   
 
 void Rectangle::display(int width, int height, bool UseCurrentValue) const
 {
     int printWidth;
     int printHeight;
 
     if (UseCurrentValue == true)
     {
         printWidth = itsWidth;       
         printHeight = itsHeight;
     }
     else
     {
         printWidth = width;         
         printHeight = height;
     }
 
     for (int i = 0; i<printHeight; i++)
     {
         for (int j = 0; j< printWidth; j++)
         {
             std::cout << "*";
         }
         std::cout << "\n";
     }
 }
 
 int main()
 {
     Rectangle theRect(30,5);
     std::cout << "display(0,0,true)...\n";
     theRect.display(0,0,true);
     std::cout <<"display(40,2)...\n";
     theRect.display(40,2);
     return 0;
 }

display(0,0,true)...
******************************
******************************
******************************
******************************
******************************
display(40,2)...
****************************************
****************************************

Implement class member function

#include <iostream> 
using namespace std; 
 
// Declare the ThreeDimension class. 
class ThreeDimension {  
public: 
  int X; 
  int Y; 
  int Z; 
 
  int range();   
}; 
 
// Implement the range member function.  
int ThreeDimension::range() { 
  return Z * Y; 
} 
 
int main() {  
  ThreeDimension aDimension; 
  ThreeDimension bDimension; 
 
  int range1, range2;  
 
  // Assign values to fields in aDimension. 
  aDimension.X = 7; 
  aDimension.Y = 16; 
  aDimension.Z = 21; 
  
  // Assign values to fields in bDimension. 
  bDimension.X = 2; 
  bDimension.Y = 14; 
  bDimension.Z = 12; 
 
  // Compute the ranges assuming a full tank of gas. 
  range1 = aDimension.range(); 
  range2 = bDimension.range(); 
  
  cout << range1 << "\n";  
 
  cout << range2;  
  
  return 0; 
}

336
168

member function overloading.

#include <iostream>
#include <math.h>
#include <stdlib.h>
using namespace std;

class absolute_value {
public:
 int number(int);
 double number(double);
};
  
int absolute_value::number(int test_data)
{
 int answer;
 answer=abs(test_data);
 return (answer);
}
double absolute_value::number(double test_data)
{
 double answer;
 answer=fabs(test_data);
 return (answer);
}
main( )
{
 absolute_value neg_number;
 cout << "The absolute value is "  << neg_number.number(-583) << endl;
 cout << "The absolute value is "  << neg_number.number(-583.1749) << endl;
 return (0);
}

Overloading class member functions

#include <iostream>
 
 class Rectangle
 {
 public:
     Rectangle(int width, int height);
     ~Rectangle(){}
 
     // overloaded class function display
     void display() const;
     void display(int aWidth, int aHeight) const;
 
 private:
     int itsWidth;
     int itsHeight;
 };
 
 Rectangle::Rectangle(int width, int height)
 {
     itsWidth = width;
     itsHeight = height;
 }
 
 
 void Rectangle::display() const
 {
     display( itsWidth, itsHeight);
 }
 
 
 void Rectangle::display(int width, int height) const
 {
     for (int i = 0; i<height; i++)
     {
         for (int j = 0; j< width; j++)
         {
             std::cout << "+";
         }
         std::cout << "\n";
     }
 }
 
 int main()
 {
     Rectangle theRect(30,5);
     std::cout << "display(): \n";
     theRect.display();
     std::cout << "\ndisplay(40,2): \n";
     theRect.display(40,2);
     return 0;
 }

display():
++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++
display(40,2):
++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++++++++++++

overloading functions in base and derived classes

#include <iostream>  
  using namespace std;  
  #include <process.h>)  
  class Stack{  
     protected:                   
        enum { MAX = 3 };         
        int st[MAX];              
        int top;                  
     public:  
        Stack()                   
        { top = -1; }  
        void push(int var)        
        { st[++top] = var; }  
        int pop()                 
        { return st[top--]; }  
  };  
  class Stack2 : public Stack  
  {  
     public:  
        void push(int var)
        {  
           if(top >= MAX-1)
              { cout << "\nError: stack is full"; exit(1); }  
           Stack::push(var);
        }  
        int pop()           
           {  
           if(top < 0)      
              { cout << "\nError: stack is empty\n"; exit(1); }  
           return Stack::pop();     
           }  
  };  
  int main()  
  {  
     Stack2 s1;  
    
     s1.push(11);                   
     s1.push(22);  
     s1.push(33);  
    
     cout << endl << s1.pop();      
     cout << endl << s1.pop();  
     cout << endl << s1.pop();  
     cout << endl << s1.pop();        
     cout << endl;  
     return 0;  
  }

overloading two class member functions

#include <iostream>
#include <math.h>
#include <string>
using namespace std;
const double DEG_TO_RAD=0.0174532925;
  
class trigonometric {
 double angle;
 double answer_sine;
 double answer_cosine;
 double answer_tangent;
public:
 void trig_calc(double);
 void trig_calc(char *);
};
void trigonometric::trig_calc(double degrees)
{
 angle=degrees;
 answer_sine=sin(angle * DEG_TO_RAD);
 answer_cosine=cos(angle * DEG_TO_RAD);
 answer_tangent=tan(angle * DEG_TO_RAD);
 cout << "\nFor an angle of " << angle << " degrees." << endl;
 cout << "The sine is " << answer_sine << endl;
 cout << "The cosine is " << answer_cosine << endl;
 cout << "The tangent is " << answer_tangent << endl;
}
  
void trigonometric::trig_calc(char *dat)
{
 char *deg,*min,*sec;
 deg=strtok(dat,"d ");  
 min=strtok(0,"m ");
 sec=strtok(0,"s");
 angle=atof(deg)+((atof(min))/60.0)+((atof(sec))/360.0);
 answer_sine=sin(angle * DEG_TO_RAD);
 answer_cosine=cos(angle * DEG_TO_RAD);
 answer_tangent=tan(angle * DEG_TO_RAD);
 cout << "\nFor an angle of " << angle << " degrees." << endl;
 cout << "The sine is " << answer_sine << endl;
 cout << "The cosine is " << answer_cosine << endl;
 cout << "The tangent is " << answer_tangent << endl;
}
main()
{
 trigonometric data;
 data.trig_calc(75.0);
  
 char str1[] = "35d 75m 20s";
 data.trig_calc(str1);
 
 data.trig_calc(145.72);
 char str2[] = "65d 45m 30s";
 data.trig_calc(str2);
 
 return (0);
}

The class member access operators . and ->

#include <iostream>
using std::cout;
using std::endl;
class MyClass 
{
public: 
   void setX( int value )
   {
      x = value;
   }
   void print() 
   { 
      cout << x << endl; 
   }
private:
   int x;  
};
int main()
{
   MyClass obj; 
   MyClass *objPtr = &obj;
   MyClass &objRef = obj;
   obj.setX( 1 );
   obj.print(); 
   objRef.setX( 2 );
   objRef.print();
   objPtr->setX( 3 );
   objPtr->print();
   return 0;  
}

1
2
3

Use class as the member function parameter type

#include<iostream.h>
#include<iomanip.h>
class Rectangle
{
private:
  float length;
  float height;
public:
  Rectangle(){}
  Rectangle(float loge,float shge)
  {
    length=loge;
       height=shge;
  }
  void getlength()
  {
    cout<<"Input large edge:";
    cin>>length;
    cout<<"Input small edge:";
    cin>>height;
  }
  void showsquare()
  {  
    cout<<setprecision(3) <<length*height<<endl;
  }
  void addsquare(Rectangle r1,Rectangle r2);
  void addedge(Rectangle r1,Rectangle r2);
};
void Rectangle::addsquare(Rectangle r1,Rectangle r2)
{
  length=r1.length+r2.length;
  height=r1.height+r2.height;
  cout<<"\n Total of Rectangle square:"
      <<r1.length*r1.height+r2.length*r2.height;
}
void Rectangle::addedge(Rectangle r1,Rectangle r2)
{
  length=r1.length+r2.length;
  height=r1.height+r2.height;
  cout<<"\n Toatal of Rectangle length:"
      <<setprecision(3)<<(length+height)*2;
}
main()
{
  Rectangle room1(15.5,6.5);
  Rectangle room2,room3;
  room2.getlength();
  cout<<"Square of room1 Rectangle is:";
  room1.showsquare();
  cout<<"square of room2 Rectangle is:";
  room2.showsquare();
  room3.addsquare(room1,room2);
  room3.addedge(room1,room2);
  return 0;
}

Input large edge:123
Input small edge:12
Square of room1 Rectangle is:101
square of room2 Rectangle is:1.48e+003
 Total of Rectangle square:1.58e+003
 Toatal of Rectangle length:314"

C++ Tutorial/Class/member method — различия между версиями

Текущая версия на 10:29, 25 мая 2010

Содержание

Declare a class with method

Default values in member functions

Implement class member function

member function overloading.

Overloading class member functions

overloading functions in base and derived classes

overloading two class member functions

The class member access operators . and ->

Use class as the member function parameter type

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Текущая версия на 10:29, 25 мая 2010 (просмотреть исходный код) Admin (обсуждение \| вклад) м (1 версия: Импорт контента...)	Текущая версия на 10:29, 25 мая 2010 (просмотреть исходный код) Admin (обсуждение \| вклад) м (1 версия: Импорт контента...)
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