You can do it in two lines, no less.
typedef struct tagRECT { long l; long t; long r; long b; } RECT;
RECT rc = {1,2,3,4};
Now if you are using the windows api, RECT is already declared, so in your method doing the following:
VOID MyMethod(void){
RECT rcTxt = { 0, 0, 10, 5 };
Declares an instance of and initialize your struct.