c structure array initializing

Question

I have structure

struct ABC {
  int a; 
  int b;
}

and array of it as

struct ABC xyz[100];

I want to in

Answer 1

With GCC you can use its extended syntax and do:

struct ABC xyz[100] = { [0 ... 99].a = 10, [0 ... 99].b = 20 };

For a portable solution I'd probably initialize one instance, and use a loop to copy that instance to the rest:

struct ABC xyz[100] = { [0].a = 10, [0].b = 20 };

for(size_t i = 1; i < sizeof xyz / sizeof *xyz; ++i)
  xyz[i] = xyz[0];

This is somewhat cleaner to me than having the actual values in the loop. It can be said to express the desired outcome at a slightly higher level.

The above syntax ([0].a and [0].b) is not an extension, it's typical C99.