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(C++) initialize

To initialize an object is to give it an initial value.

There are multiple types of initialize:

• list initialization
• memberwise initialization

There are four initialization styles, prefer the first (called list initialization) [1].

1. T a { b };
2. T a = { b };
3. T a = b;
4. T a(b);

Advice

• Prefer {} initialization over = and () initialization [1]
• Initialize members and bases in their order of declaration [2]
• Although it is not always necessary to initialize every variable explicitly, doing so will help you avoid many kinds of problems [3]

Examples

• initialize example 1: a difference between {} and = with references
• initialize example 2: initializing a reference member variable

References

1. Bjarne Stroustrup. The C++ Programming Language (4th edition). 2013. ISBN: 978-0-321-56384-2. Chapter 17.7. Advice, page 525: '[6] Prefer {} initialization over = and () initialization'
2. Bjarne Stroustrup. The C++ Programming Language (4th edition). 2013. ISBN: 978-0-321-56384-2. Chapter 17.7. Advice, page 525: '[9] Initialize members and bases in their order of declaration'
3. Paul Deitel, Harvey Deitel. C++11 for progrgrammers (2nd edition). 2014. ISBN: 978-0-13-343985-4. Chapter 2.4, Error Prevention Tip 2.1. page 25: 'Although it is not always necessary to initialize every variable explicitly, doing so will help you avoid many kinds of problems.'

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