Do I need to consider the possible mismatched brackets? Like:

func((1+2, foo)

Am I supposed to use %d or %f according to the different return values of the expression?

And what is the maximum recursive depth of the expression?

print (  (func(1, (2 + 3) * 2.9, func1(2) + func2())) )

printf("%d", func(1, (2 + 3) * 2.9, func1(2) + func2()));