Copying elements of array to a new one - C

Question

I'm currently doing a school assignment and now I'm really stuck. The problem I have is that When I'm trying to copy the elements of the array dice to the array diceCheck the program goes in to some kind of infinite loop and I don't understand why. Help would be greatly appreciated! Edit: It's in the bottom in the function printScores.

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

void printMenu(void);
void throwDice(int dice[], int nrOfDice, int nrOfDieValues);
void readDieValues (int dice[], int nrOfDice);
void printDice(const int dice[], int nrOfDice);
void printScores(const int dice[], int nrOfdice, int nrOfDieValues);
int isThreeOfAKind(const int dieValues[], int nrOfDieValues);
int isSmallStraight(const int dieValues[], int nrOfDieValues);

int main(void)
{
    const int nrOfDice = 5;
    const int nrOfDieValues = 6;
    int dice[4], menuChoice = 0;

    printMenu();
    printf("\nMake your choice: ");
    while(scanf("%d", &menuChoice) != -1)
    {
        switch (menuChoice)
        {
            case 0:
                printMenu();
            break;
            case 1:
                throwDice(dice, nrOfDice, nrOfDieValues);
                printf("Make your choice: ");
            break;
            case 2:
                readDieValues(dice, nrOfDice);
                printf("Make your choice: ");
            break;
            case 3:
                printDice(dice, nrOfDice);
                printf("Make your choice: ");
            break;
            case 4:
                printScores(dice, nrOfDice, nrOfDieValues);
            break;
            case -1:
                return 0;
            break;
            default:
                printf("Invalid choice!\n");
            break;
        }
    }
    return 0;
}

void printMenu()
{
    printf("MENU:\n");
    printf("0.  Display the menu\n");
    printf("1.  Make a random throw\n");
    printf("2.  Enter die values for a throw\n");
    printf("3.  Display the die values for the throw\n");
    printf("4.  Display the score for the throw\n");
    printf("-1. End program\n");
}

void throwDice(int dice[], int nrOfDice, int nrOfDieValues)
{
    int choice, i;
    printf("Enter seed (1 gives a random seed): ");
    scanf("%d", &choice);
    if(choice == 1)
    {
        srand(time(NULL));
        for (i = 0; i < nrOfDice; i++)
        {
            dice[i] = ( rand() % nrOfDieValues) + 1;
        }
        printf("\n");
    }
    else
    {
        srand(choice);
        for(i = 0; i < nrOfDice; i++)
        {
            dice[i] = ( rand() % nrOfDieValues) + 1;
        }
        printf("\n");
    }
}

void readDieValues(int dice[], int nrOfDice)
{
    int i;
    for(i = 0; i < nrOfDice; i++)
    {
        printf("Die %d: ", (i+1));
        scanf("%d", &dice[i]);
    }
}

void printDice(const int dice[], int nrOfDice)
{
    int i;
    printf("Your dice: ");
    for(i = 0; i < nrOfDice; i++)
    {
        printf("%d ", dice[i]);
    }
    printf("\n\n");
}

int isThreeOfAKind(const int dieValues[], int nrOfDieValues)
{
}

int isSmallStraight(const int dieValues[], int nrOfDieValues)
{
}

void printScores(const int dice[], int nrOfdice, int nrOfDieValues)
{
    int diceCheck[4], i;

    for(i = 0; i < nrOfdice; i++)
    {
        diceCheck[i] = dice[i];

        printf("%d ", dice[i]); //these are just for myself to check if it worked
        printf("%d ", diceCheck[i]); //these are just for myself to check if it worked
    }
}

Generally when pasting code here, you should only paste the least amount of code required to illustrate your problem. Also, please try reduce the amount of unnecessary blank lines. — Lee Taylor
– Lee Taylor, Commented Oct 8, 2014 at 2:56

M.M · Accepted Answer · 2014-10-08 01:42:46Z

1

You have:

const int nrOfDice = 5;

but

int dice[4];
int diceCheck[4];

Your copying idea is correct but you are going one past the end of the array.

To avoid this sort of error, initialize both from the same expression, e.g.:

int dice[4];
const int nrOfDice = sizeof dice / sizeof dice[0];

or

const int nrOfDice = 4;
int dice[nrOfDice];

and inside the PrintScores function, instead of int diceCheck[4];, do:

int diceCheck[nrOfDice];

answered Oct 8, 2014 at 1:42

M.M

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2 Comments

Rasmus Nordlander Over a year ago

Thank you very much, that did solve it! :) Just out of curiosity, would e.g. int dice[5] and diceCheck[5] have worked? Even though if I were to write it like that the nrOfDice would have no use but still, so that I can understand a bit easier. I should have realized earlier to use the nrOfDice instead of "numbers", but now I know. Thanks man :)

M.M Over a year ago

Yes that would work, but it is error-prone to have your progrma rely on the same number appearing in two different places.

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