Write a program that simulates a vending machine. The user will be prompted to enter a letter then a number. As part of the prompt you must display a message to indicate the number and letter, along with the possible choices. That is, what selections will give user which item. If the user enters a number or a letter that is not valid, then display the message Bad Entry and end the program.

Selections with messages.

a1 - display the message Here are your chips

a2 - display the message Here is your soda

b1 display the message Here is your candy bar

b2 display the message Here is your popcorn

Sample display

This is a vending machine.

Here are your choices.

a1 - chips

a2 - soda

b1 - candy bar

b2 - popcorn

Enter letter: a

Enter number: 2

Here is your soda.