C++ Tutorial/Class/initialization syntax — различия между версиями
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Версия 14:21, 25 мая 2010
Initialize numA and numB inside the MyClass constructor using normal syntax
#include <iostream>
using namespace std;
class MyClass {
int numA;
int numB;
public:
MyClass(int x, int y) {
numA = x;
numB = y;
}
int getNumA() { return numA; }
int getNumB() { return numB; }
};
int main()
{
MyClass ob1(7, 9), ob2(5, 2);
cout << "Values in ob1 are " << ob1.getNumB() <<
" and " << ob1.getNumA() << endl;
cout << "Values in ob2 are " << ob2.getNumB() <<
" and " << ob2.getNumA() << endl;
return 0;
}Values in ob1 are 9 and 7 Values in ob2 are 2 and 5
Initialize parameters in base class
#include <iostream.h>
class Pointer
{
private:
long x,y;
public:
Pointer(long a=0,long b=0) {
x=a;
y=b;
}
long GetX(){
return x;
}
long GetY(){
return y;
}
void Disp(){
cout << "x=" <<x<<" y="<<y;
}
};
class Pointer3D : public Pointer
{
long z;
public:
Pointer3D(long a=0,long b=0,long c=0):Pointer(a,b){
z=c;
}
long GetZ(){ return z;}
void Disp()
{
cout <<"x= "<<GetX()<<" y="<<GetY();
cout << " z="<< z <<endl;
}
};
main()
{
Pointer3D p1;
Pointer3D p2(3,-4);
p2.Disp();
p2=p1;
p2.Disp();
return 0;
}x= 3 y=-4 z=0 x= 0 y=0 z=0
Initialize variables from base class using initialization syntax
#include <iostream>
using namespace std;
class MyClass {
const int numA; // const member
const int numB; // const member
public:
MyClass(int x, int y) : numA(x), numB(y) { }
int getNumA() { return numA; }
int getNumB() { return numB; }
};
int main()
{
MyClass ob1(7, 9), ob2(5, 2);
cout << "Values in ob1 are " << ob1.getNumB() <<
" and " << ob1.getNumA() << endl;
cout << "Values in ob2 are " << ob2.getNumB() <<
" and " << ob2.getNumA() << endl;
return 0;
}Values in ob1 are 9 and 7 Values in ob2 are 2 and 5
