Write a C++program including two functions named gcd(), lcm() besides main() function. Please use function prototype to define these two functions first, then implement them. The gcd refers to the Greatest Common Divisor, while lcm refers to Lowest Common Multiple. In the gcd() function, please use Euclidean algorithm to find the greatest common divisor of the two different input integers (The two input integers are both greater than one). The parameters of gcd(), lcm() are supposed to be like gcd(int a, int b), lcm(int a, int b). Also, implement the function lcm() based on the mathematical relationship between GCD and LCM.