Each credit card number issued by Vita Credit contains five digits. The last digit is
determined by multiplying the second and fourth digit by three and then adding the
products to the first and third digits. The last digit in the sum is then appended to the first
four digits in the credit card number, as shown in the following example.
Fifth Digit Algorithm
First four digits in credit card number: 1 3 5 7
Step 1: Multiply the second and fourth digits by 2: 3*2 and 7*2
Result 1 6 5 14
Step 2: Add the numbers together: 1 + 6 + 5 + 14 = 26
Step 3: Take the last digit in the sum and append it to the first four digits, resulting in the
final credit card number: 13576
In this assignment, you are required to complete the given incomplete application which
takes four digits and then calculate the fifth digit and display the credit card number. The
name of the solution, project, and form file are Vita Solution, Vita Project, and Main
The interface of this application is shown as follows:
look at Vita Gif
Use the provided interface for this assignment.
The application includes following Function and Sub Procedures.
Function/Sub procedure Description
exitButton_Click Define exitButton click event.
firstFourTextBox_Enter Select existing text of the firstFourTextBox.
firstFourTextBox_KeyPress Allows only numbers and the Backspace key for the
firstFourTextBox_TextChanged Clear the content of the firstFourTextBox.
creditNumberButton_Click Define creditNumberButton click event (Determines the fifth
digit in a credit card number).
You must complete the following parts in the given application.
1. Declare two String variables called creditNum, fifthDigit and an integer variable
called sumOfDigits. (9 points)
2. Write code to get the value at firstFourTextBox to the variable creditNum. (5 points)
3. Fill the two blanks in if statement to check whether the creditNum is a four digit
string. (6 points)
4. Write code to get the summation of four digits in variable creditNum to the variable
sumOfDigit. You must follow the above given scenario to get the summation.
5. Write code to find the fifth digit and store in the variable fifthDigit. (10 points)
6. Write code to append fifth digit to first four digits in the variable creditNum.