Initialization of all elements of an array to one default value in C++?

Question

C++ Notes: Array Initialization has a nice list over initialization of arrays. I have a

int array[100] = {-1};

expecting it to be full with

Answer 1

Using the syntax that you used,

int array[100] = {-1};

says "set the first element to -1 and the rest to 0" since all omitted elements are set to 0.

In C++, to set them all to -1, you can use something like std::fill_n (from ):

std::fill_n(array, 100, -1);

In portable C, you have to roll your own loop. There are compiler-extensions or you can depend on implementation-defined behavior as a shortcut if that's acceptable.