Your question is a bit misleading, I'm having trouble understanding what you mean with "in between". I'm assuming you want the biggest number from an input of 3 numbers. You did not specify what should happen if more than one number is the biggest (ie., they're equal).
A very naive implementation might be:
void PrintBiggest(int a, int b, int c) { if ((a >= b) && (a >= c)) cout << a; else if ((b >= a) && (b >= c)) cout << b; else if ((c >= a) && (c >= b)) cout << c; }
If you want to use STL (mine is a little rusty), the following could be the start of something more generic:
void PrintBiggest(int a, int b, int c) { std::vector<int> myints; myints.push_back(a); myints.push_back(b); myints.push_back(c); sort(myints.begin(), myints.end()); cout << myints.back(); }