Coupon code generation

Question

I would like to generate coupon codes , e.g. AYB4ZZ2. However, I would also like to be able to mark the used coupons and limit their global number, let\'s say <

Answer 1

You can use a base-36 number system. Assume that you want 6 characters in the coupen output.

pseudo code for MakeCoupon

MakeCoupon(n) {

Have an byte array of fixed size, say 6. Initialize all the values to 0. convert the number to base - 36 and store the 'digits' in an array (using integer division and mod operations) Now, for each 'digit' find the corresponding ascii code assuming the digits to start from 0..9,A..Z With this convension output six digits as a string.

}

Now the calculating the number back is the reverse of this operation.

This would work with very large numbers (35^6) with 6 allowed characters.