How can an array be initialized in a constructor?

Question

Possible Duplicate:
initialize a const array in a class initializer in C++

If I have a class with a member variable that is an array of bools, how can I initialize the array in the initializer list of the constructor to all false values? Or will they be initialized by default to all false?

class example {
public:
  example()
    : // What goes here to initialize _test to 64 false values?
  {
  }

private:
  bool _test[64];
};

No, by default they aren't initialized to nothing. Can't you iterate over all elements? — DonCallisto, Feb 15 '12 at 12:52
Why not just a for-loop in the constructor to do it? You could also use memset which is even more efficient. — guitarflow, Feb 15 '12 at 12:52
[This has already been answered](http://www.google.com/url?q=http://stackoverflow.com/questions/161790/initialize-a-const-array-in-a-class-initializer-in-c&sa=U&ei=B6o7T5eAB8Pu0gGE2cjVCw&ved=0CBcQFjAB&sig2=4ZeSnYECc7vy7ngjYj3YOQ&usg=AFQjCNG7PSUZXNuACyocYKjMa75gOtQg1g) — SplinterOfChaos, Feb 15 '12 at 12:51
@guitarflow :Assigning the elements to 0 inside the for-loop (inside the constructor) is not **initialization**. — Prasoon Saurav, Feb 15 '12 at 12:59

score 2 · Answer 1 · answered Feb 15 '12 at 12:51

2

example() :_test()
    : // zero initialization
  {
  }

answered Feb 15 '12 at 12:51

Prasoon Saurav

91,295
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This works? I guess with bools this would preset the array with false values? – guitarflow Feb 15 '12 at 12:54
@guitarflow : The question says "how can I initialize the array in the initializer list of the constructor to all **false** values?" – Prasoon Saurav Feb 15 '12 at 12:55
Of course, I have just never seen this form before. Can you also use that to initialize it to some other int value or true in case of bool? – guitarflow Feb 15 '12 at 13:03
@guitarflow : No we can only use this to zero (value initialize in case of non PODs) initialize the elements. – Prasoon Saurav Feb 15 '12 at 13:09

score 1 · Accepted Answer · answered Feb 15 '12 at 12:52

1

something like:

class example {
public:
  example()
    : _test()
  {  
  }

private:
  bool _test[64];
};

answered Feb 15 '12 at 12:52

Nim

33,299
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How can an array be initialized in a constructor?

2 Answers2