The compiler will give an error for such declarations
int a, b, c = 10, 15, 20;
The only idea that comes to my mind is the following :)
int a, b, c = ( a = 10, b = 15, 20 );
Or you can make these names members of the structure data.
struct { int a, b, c; } s = { 10, 20, 30 };
EDIT: =?
. . .:)