1. Write a program that has the main() call a user-defined function that takes a Celsius temperature value as an argument and then returns the equivalent Fahrenheit value. The program should request the Celsius value as input from the user and display the result, as shown the following code:
Please enter a Celsius value: 20
20 degree Celsius is 68 degree Fahrenheit.
Note: You should include the input validation when you take the input value.
[Fahrenheit=1.8 * Celsius + 32.0]
2. What is purpose of the constructor? Illustrate with an example.