'scowls at darkerstone knight'
Instring works by returning the position of a string inside of another string. for example 'a' has a position of 1 in string 'abcdef'. The way you could make this work for your card game is have all the cards values stored into a string. 'A1234567890JQK' 0 being a 10. (That might be the wrong order, i'm not an expert') and then another string to classify its suit. 'HSCD' Hearts, Spades, Clubs, Diamonds.
You could then identify each card by a number. 12,2 would be the Jack of Spades. The numbers would help in ranking the kard as well. A 9,2 would be worth more than a 4,2. You could then denote your hand by a list of numbers.
9,2,5,4,2,1,7,3,13,3,6,1,2,2 for example would be a 7 card hand. Every two elements of the list represents 1 card, 14 elements being 7 cards.
In order to find out if you have doubles or triples or such, you could set up a system to find patterns in the numbers. I won't try to write this out for you, but i will give an example idea for finding singles and doubles.
The program first sets up a card list with 13 elements all at 0 for all 13 types of cards
The program goes through every even element of the list, and adds a 1 to the element in the card list that corresponds to the number that it finds. For example if the program found a 3 in the first element, it would add a 1 to element 3 of the card list.
At the end, if any of the elements in the card list had a 2, we know that you have two of the card that is represented by that element. This program could also be adapted to finding threes or fours as well.
As for finding other combinations such as flushes, full houses, straits, and so on, you will have to think of those on your own. Although feel free to ask any questions.