Write C++ Code in single source file (.cpp file) containing following user defined functions:

1. IsEven- takes an integer input (one argument of type int) and return true or false.

2. IsPositive- takes a float input (one argument of type double) and return a Boolean value. The function returns the true if its argument is positive and false if its argument is zero or negative.

3. IsPrime- takes an integer input and return true or false.

4. NumOfDigits- takes an integer input and return number of digits in that integer.

Instructions: After writing these functions, show usage of these functions in main () function by calling these functions and showing their output.