given three integer numbers and knowing that they form a valid triangle as (int side1, int side2, int side3), how can I use c++ library function max () to write a single statement that assigns the maximum of three sides to the variable sidemax;

Answer 1

I don't know about the max() function but assuming it gives the maximum of two variables...

sidemax = max(max(side1, side2), side3) ;

Answer 2

will this work?

sidemax = max((side1>side2:side1,side2),side3);