Initialization of all elements of an array to one default value in C++?
arrays, c++, default-value, initialization, variable-assignment
Solution
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 `<algorithm>`):
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.
Problem
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 -1's but its not, only first value is and the rest are 0's mixed with random values. The code ``` int array[100] = {0}; ``` works just fine and sets each element to 0. What am I missing here.. Can't one initialize it if the value isn't zero ? And 2: Is the default initialization (as above) faster than the usual loop through the whole array and assign a value or does it do the same thing?