c - Syntax to set an array-of-structs element via initializer? -

i have following c code:

typedef struct {     int x,y; } point2d;  point2d data[5];

later in code (i.e. not during initialization of data), want set individual elements of data x/y values. two-statement-code simple:

point2d pt = {.x = a, .y = b}; data[3] = pt;

but there way in c in single statement? neither of following ideas seems valid c99 code (for gcc 4.8.2):

data[3] = {.x = a, .y = b}; data[3] = point2d{.x = a, .y = b}; data[3] = point2d(a,b); //c++-like syntax

use compound literal:

data[3] = ( point2d ){.x = a, .y = b};

GCM