Suppose you have two functions with the following function declarations:

double cool$\_$fun $($ double $,$ double$)$; $//1$

double cool$\_$fun $($double $,$ int $)$; $//2$

Which function definition should be used in the following function calls? $($Write the function number in the box, $1$ or $2)$

double x$,$ y$(1\mathrm{.}0)$;

x $=$ cool$\_$fun $($ y$,6\mathrm{.}0)$;

x $=$ cool$\_$fun $(5,6)$;

x $=$ cool$\_$fun $(5,6\mathrm{.}0)$;