第七周C++ 任务三。模板类设计Complex，使实部和虚部为定义对象时用的实际类型

【任务3】阅读P314的例10.1（电子版的在平台上见txt文件）。该例实现了一个复数类，但是美中不足的是，复数类的实部和虚部都固定是double型的。可以通过模板类的技术手段，设计Complex，使实部和虚部的类型为定义对象时用的实际类型。
（1）要求类成员函数在类外定义。
（2）在此基础上，再实现减法、乘法和除法
你可以使用的main()函数如下。
int main( )
{ Complex<int> c1(3,4),c2(5,-10),c3; 
 c3=c1.complex_add(c2); 
 cout<<"c1+c2=";
 c3.display( ); 
 Complex<double> c4(3.1,4.4),c5(5.34,-10.21),c6; 
 c6=c4.complex_add(c5); 
 cout<<"c4+c5=";
 c6.display( );
 system("pause");
 return 0;
}

附：例10.1的代码
#include <iostream>
using namespace std;
class Complex  
{
public:
 Complex( ){real=0;imag=0;}    
 Complex(double r,double i){real=r;imag=i;}
 Complex complex_add(Complex &c2);
 void display( );  
private:
 double real;
 double imag;
};
Complex Complex::complex_add(Complex &c2)
{
 Complex c;
 c.real=real+c2.real;
 c.imag=imag+c2.imag;
 return c;
}  
void Complex::display( )  
{
 cout<<"("<<real<<","<<imag<<"i)"<<endl;
}
int main( )
{
 Complex c1(3,4),c2(5,-10),c3; 
 c3=c1.complex_add(c2); 
 cout<<"c1="; c1.display( ); 

 

#include <iostream>
using namespace std;
template <class numtype>
class Complex   
{
public:
	Complex( ){real=0;imag=0;}     
	Complex(double r,double i){real=r;imag=i;} 
	Complex complex_add(Complex &c2);    
    Complex complex_subtract(Complex <numtype> &c2);   
    Complex complex_multiply(Complex <numtype> &c2);   
    Complex complex_divide(Complex <numtype> &c2);   
	void display( );   
private:
	double real; 
	double imag; 
};
template <class numtype>
Complex<numtype> Complex<numtype>::complex_add(Complex <numtype> &c2)
{
	Complex <numtype> c;
	c.real=real+c2.real;
	c.imag=imag+c2.imag;
	return c;
}  
template <class numtype>
Complex<numtype> Complex<numtype>::complex_subtract(Complex <numtype> &c2)  
{
	Complex <numtype> c;
	c.real=real-c2.real;
	c.imag=imag-c2.imag;
	return c;
}
template <class numtype>
Complex<numtype> Complex<numtype>::complex_multiply(Complex <numtype> &c2) 
{
	Complex <numtype> c;
	c.real=real*c2.real-imag*c2.imag;
	c.imag=imag*c2.real+real*c2.imag;
	return c;
}
template <class numtype>
Complex<numtype> Complex<numtype>::complex_divide(Complex <numtype> &c2)
{
	Complex <numtype> c;
	c.real=(real*c2.real+c2.imag*imag)/(real*real+imag*imag);
	c.imag=(c2.imag*real-c2.real*imag)/(real*real+imag*imag);
	return c;
} 
template <class numtype>
void Complex<numtype>::display( )   
{
	cout<<"("<<real<<","<<imag<<"i)"<<endl;
}

int main( )
{	
	Complex<int> c1(3,4),c2(5,-10),c3;  
	c3=c1.complex_add(c2);  
	cout<<"c1+c2="; 
	c3.display( );
	
	c3=c1.complex_subtract(c2) ;
	cout<<"c1-c2="; 
	c3.display( );

	c3=c1.complex_multiply(c2);  
	cout<<"c1*c2="; 
	c3.display( );
	
	c3=c1.complex_divide(c2); 
	cout<<"c2/c1="; 
	c3.display( );


     
	
    Complex<double>	c4(3.1,4.4),c5(5.34,-10.21),c6;
	c6=c4.complex_add(c5);  
	cout<<"c4+c5="; 
	c6.display( );
	
	c6=c4.complex_subtract(c5) ;
	cout<<"c4-c5="; 
	c6.display( );

	c6=c4.complex_multiply(c5);  
	cout<<"c4*c5="; 
	c6.display( );
	
	c6=c4.complex_divide(c5) ;
	cout<<"c5/c4="; 
	c6.display( );
	system("pause");
	return 0;
}

 

 

感言：掌握了类模板这个程序没有太大难度。
但在public里作声明时还有必要加上

Complex complex_subtract(Complex <numtype> &c2);

Complex complex_multiply(Complex <numtype> &c2);

Complex complex_divide(Complex <numtype> &c2);

 

中的<numtype>吗？