You MUST use switch statement to complete the following. Write a program to achieve a four-function calculator. The program will first take two real (non-zero) numbers as input from the user. You can safely assume the user will always input two numbers. The program then outputs the following message to prompt another user input:

Please select:
: add two numbers.
-: subtract two numbers.
*: multiple two numbers.
/: divide two numbers.

The user then enters one of the above characters for the program to perform the corresponding calculation on the previously two numbers. If the user enters other character than the above, the program will print out Unknown calculation and exits.

Ex: if the user enters: 2.5 4 *
the program will output: 2.5 * 4