C++ Programming Code Examples C++ > Beginners Lab Assignments Code Examples C++ built-in function C++ built-in function Built-in functions are also known as library functions. We need not to declare and define these functions as they are already written in the C++ libraries such as iostream, cmath etc. We can directly call them when we need. Here we are using built-in function pow(x,y) which is x to the power y. This function is declared in cmath header file so we have included the file in our program using #include directive. #include <iostream> #include <cmath> using namespace std; int main(){ /* Calling the built-in function pow(x, y) which is x to the power y We are directly calling this function */ cout<<pow(2,5); return 0; }