C + +: All parameters that use non-member functions (NON-MEMBER) to handle functions require type conversions

Some functions, all parameters need to use type conversion, such as multiplication, write a rational number class rational, need to perform multiplication operations:

function satisfaction: Rational = rational*double; Rational = double*rational; You need to use a non-member function (Non-member);

The initiator of a member function must be a class, because a double type may occur before the multiplication can be performed, so you should use a non-member function;

When executing: that is, Rational = rational*rational (double); Rational = rational (double) *rational, an implicit conversion occurred.

Code:

* * * test.cpp * *  Created on:2014.04.22 * 
 author:spike/
      
/*eclipse CDT, gcc 4.8.1* /
      
#include <iostream>/  
      
/Rational number  
class Rational {public  
:  
    rational (double numerator = 0, Double denominator = 1):  
        m_n (numerator), m_d (denominator) {}  
    double numerator () const {return m_n;};  
    Double denominator () const {return m_d;};  
    Double value () {return (m_n/m_d);}  
Private:  
    double m_n;  
    Double m_d;  
};  
      
Const Rational operator* (const rational& LHS,  
        const rational& RHS) {return  
    Rational (Lhs.numerator () *rhs.numerator (),  
            lhs.denominator () *rhs.denominator ());  
}  
      
int main (void) {  
    Rational Onefourth (1, 4);  
    Rational result;  
    result = Onefourth * 3.5;  
    result = 3.5 * Onefourth;  
    Std::cout << "result =" << result.value () << Std::endl;  
      
    return 0;  
}

Output:

result = 0.875

Author: csdn Blog spike_king

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