How to initialize all members of an array to the same value?

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清歌不尽
清歌不尽 2020-11-21 04:34

I have a large array in C (not C++ if that makes a difference). I want to initialize all members of the same value.

I could swear I

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  •  陌清茗
    陌清茗 (楼主)
    2020-11-21 05:00

    Unless that value is 0 (in which case you can omit some part of the initializer and the corresponding elements will be initialized to 0), there's no easy way.

    Don't overlook the obvious solution, though:

    int myArray[10] = { 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 };
    

    Elements with missing values will be initialized to 0:

    int myArray[10] = { 1, 2 }; // initialize to 1,2,0,0,0...
    

    So this will initialize all elements to 0:

    int myArray[10] = { 0 }; // all elements 0
    

    In C++, an empty initialization list will also initialize every element to 0. This is not allowed with C:

    int myArray[10] = {}; // all elements 0 in C++
    

    Remember that objects with static storage duration will initialize to 0 if no initializer is specified:

    static int myArray[10]; // all elements 0
    

    And that "0" doesn't necessarily mean "all-bits-zero", so using the above is better and more portable than memset(). (Floating point values will be initialized to +0, pointers to null value, etc.)

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