Find the largest number from a set of define and set a define from the answer

[guix]

Something like this maybe

#define highestNum \
(\
	numA > numB ?\
		numA > numC ?\
			numA > numD ?\
				numA :\
			numD :\
		numC :\
	numB > numC ?\
		numB > numD ?\
			numB :\
		numD :\
	numC > numD ?\
		numC :\
	numD \
)