do you actually know C? these sorts of things are usually taught early on
whenever i program in C (not too often i must admit) i would do something as follows:
// Your other includes, main() function whatever
cout << "Enter a number: ";
cin >> Input;
then again, i had someone new to C complaining about that saying it should be #include <iostream> and using std::cout rather than just cout. Iv been doing Java mostly of late so not totally up to speed
EDIT - i dont know if your question is more about whether you can use the same code in Linux as you would when coding in windows, to bring the Dos prompt. Its normally exactly the same.