Question:

A Credit Card company uses a method to generate its own valid Card Numbers. Given 7-digit Customer Number, a Card Number is generated, consisting of 9 digits. The Method is as follows:

It gets the 3-digit number from the middle of the given Customer number,

It takes the square of this 3-digit number

It adds one to this square if the first digit of the customer number is EVEN.

It appends the last two digits of the result to the end of the Customer Number.

For Example:

Given Customer Number : 1234567

Number to be squared : 345

Square of it : 345 * 345 = 119025

Last 2 digits : 25

Resulting Card Number : 123456725

Write a C program that will input a 9-digit Credit Card Number, and will check whether iit is valid or not (i.e. to examine if the last 2 digits of the Credit Card Number can be generated from the first 7-digit number)

Hint : use 'long' data type. Placeholder in printf or scanf is %ld for long data

To solve this problem:

1. input a 9-digit number (credit card number)

2. store the first 7 digit number to a variable, say cust; and last two digit to another variable, say last2.

3. find the middle 3 digit number of cust and take square of it.

4. If the first digit of cust is even, add one to this square. (for finding if it is even use %2 operation to the first digit. I hope you know how to find first digit !...)

5. compare the result with the value last2 (found on step 2) and display the corresponding message if it is valid or not...