Problem passing arguments by reference

Question

Okay, so I'm trying to pass two variables to a function by reference, but when I go to arithmetically manipulate the variables in the function that's receiving the arguments, it's multiplying their values by four, for what reason I cannot understand. Here's my code (the relevant parts of it) -- it's a casino game:
void BuyChips(int *, int *);
int main()
    int money = 5000;
    int chips = 0;
    BuyChips(money, chips);
void BuyChips(int *mny, int *chps)
    int numChipsBought;
    printf("How many chips would you like to buy? ");
    scanf("%d", &numChipsBought);
    chps += numChipsBought;
    mny -= numChipsBought;
    printf("\nYou purchase $%d in chips. You now have $%d in chips
            and $%d remaining in cash.", numChipsBought, chps, mny);
If I type in "20" for the input for how many chips I want to buy, here's the output I get:
You purchase $20 in chips. You now have $80 in chips and $4920 remaining in cash.
For the life of me I can not figure this out. I can't figure out why it has multiplied the values by four. I know it has something to do with passing the arguments to the function by reference, though, because (for debugging's sake) I tried creating regular variables for chips and money within the BuyChips() function itself instead of passing them to the function from main(), and it worked fine. But for some reason, when I pass the variables there by reference, it multiplies them by four.
Can someone please help me with this? Thanks!

Answer 1

nt main()
    int money = 5000;
    int chips = 0;
     BuyChips( &money, &chips);
     (send the address of the variables)
     *chps += numChipsBought;
     *mny -= numChipsBought;
    printf("\nYou purchase $%d in chips. You now have $%d in chips
            and $%d remaining in cash.", numChipsBought, *chps, *mny);
(access the variable through the address)