Come to think of it, that's the only way you can do it because Lite-C does not allow you to initialize with variables.
Code
int fx_add(int a,int b){return a+b;}
int fx_subtract(int a,int b){return a-b;}
int fx_multiply(int a,int b){return a*b;}
int fx_divide(int a,int b){return a/b;}
int fx(int a,int b); //prototype
int do_fx(DWORD ptr, int a, int b){fx=ptr; return fx(a,b);}
void main(){
	set(LOGFILE);
	DWORD fptrs[4];
	fptrs[0]=fx_add;
	fptrs[1]=fx_subtract;
	fptrs[2]=fx_multiply;
	fptrs[3]=fx_divide;
	int i;
	for(i=0;i<4;i++){
		int a=10,b=2;
		int out = do_fx(fptrs[i],a,b);
		printf("\n[%d](%d,%d)=%d",i,a,b,out);
	}
	printf("\nDone!");
}

/* OUTPUT:
[0](10,2)=12
[1](10,2)=8
[2](10,2)=20
[3](10,2)=5
Done!
*/