randomize() and random() functions in c++ work only in certain compilers

I learn C++ in school and there we use Turbo C++. However at home I use either Dev C++ or terminal in Ubuntu to compile programs.
The functions randomize() and random() are used regularly and we include stdlib.h to call them. But in Dev and terminal i get an error saying that the function does not exist.
What could be the reason for this and what can I use as a substitute?