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Lesson 12 - Assignment operator

In the previous lesson, Copy Constructors in C++, we were dealing with C++ copy constructors. In today's C++ tutorial, we're going to look at the assignment operator, which is another basic operation we're going to overload.

What's the assignment operator? It's the equals symbol we regularly use. For example, the code x = 4 + 5 calls the assignment operator on the x object (if it's an object). Let's try to create two warriors, then we'll to overwrite one with the other:

Warrior a(100, 8, 5, die);
Warrior b(100, 9, 6, die);
a = b;

The compiler reports an error that the "equals" operator isn't defined. Specifically (for Visual Studio), the message looks like this:

error C2280: 'Warrior &Warrior::operator =(const Warrior &)': attempting to reference a deleted function
note: compiler has generated 'Warrior::operator =' here

We usually want to be able to assign a variable to another variable of the same type. Unlike in higher programming languages, we have to take care of this in C++ ourselves (yes, again).

The Assignment Operator

First, let's try to think logically about the declaration. The method name is obvious - the operator keyword followed by the equals symbol. What about parameters? We want to take another instance and copy its value. At the same time we assume that


 

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In this C++ tutorial, we'll look at the assignment operator. We'll learn when it's called, what it's used for and how to implement it.

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Article has been written for you by David Capka
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The author is a programmer, who likes web technologies and being the lead/chief article writer at ICT.social. He shares his knowledge with the community and is always looking to improve. He believes that anyone can do what they set their mind to.
Unicorn College The author learned IT at the Unicorn College - a prestigious college providing education on IT and economics.
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