Compound assignment operator overloading

Question

I have seen Boost give you the possibility of doing:

v*=c where c is i.e. a double and v is a vector

How could I make, as an exercise, the overloading of *= correctly, which works in the same way of the previous example (with double on the right side)?

ForEveR · Accepted Answer · 2015-04-29 10:11:17Z

2

How about something like this?

// in class
T& operator *= (double d)
{
   member *= d;
   return *this;
}

// outside of class
T operator * (T v, double d)
{
   v *= d;
   return v;
}

answered Apr 29, 2015 at 10:11

ForEveR

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5 Comments

maja Over a year ago

You're missing an = in the second example

ForEveR Over a year ago

@maja it's not example, it's overloading of operator * just for consistence.

maja Over a year ago

Then your code is modifying the parameter v, which shouldn't happen when you write v1 = v * 4.2;

ForEveR Over a year ago

@maja it's copy, real object will not be modified.

maja Over a year ago

Damn, you're right. pass-by-value. Embarrassing that I didn't see it.

maja · Accepted Answer · 2015-04-29 10:12:38Z

0

Your method will look as follows:

inline vector operator *= (vector v, double &b);

It's overloaded for the class vector, should take a double, should modify the object itself and should return itself to be used as v1 = v2*= 4.2;

Since it's for an exercise, you won't post the implementation here.

answered Apr 29, 2015 at 10:12

maja

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