CODEWITHSUNDEEP
c++overloadingadditionvariable-assignmentoperator-keyword
greg phillip
greg phillip

Reputation: 161

Difference between compound assignment and operator

I want to overload two operators: += and +

what is basically the difference between them? is += just modifying the current object and + returns a new object?

Upvotes: 1

Views: 473

Answers (1)

Horstling
Horstling

Reputation: 2151

It's just like you said, operator+= works in-place (it modifies the current object), while operator+ returns a new object and leaves its parameters unchanged.

A common way to implement them for a type T is as follows:

// operator+= is a member function of T
T& T::operator+=(const T& rhs)
{
    // perform the addition
    return *this;
}

// operator+ is a free function...
T operator+(T lhs, const T& rhs)
{
    // ...implemented in terms of operator+=
    lhs += rhs;
    return lhs;
}

Upvotes: 4

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