Question

Possible Duplicate:
How to get the size of dynamically allocated 2d array

I can’t find what I did wrong here. I want to create an array which its size is based on user input, get the data (integers) for the array from user input, and print the array integers.

The problem is that it only prints the first array element, i.e intArr[0].

int main()
{
    int i, n, *intArr;

    printf("Type the array size:\t");
    scanf("%d", &n);

    intArr = (int *)malloc(n * sizeof(int));

    for (i = 0; i < n; ++i)
    {
        printf("Type a number\t");
        scanf("%d", intArr + i);
    }

    printArr(intArr);
}

void printArr(int *arr)
{
    int i; 
    for (i = 0; i < (sizeof(arr) / sizeof(*arr)); ++i)
        printf("%d ", *(arr + i));
}

Answer 1

The type of arr is an int* so sizeof(arr) will be the sizeof(int*) and not the number of elements in arr. On your system sizeof(int*) and the sizeof(int) is the same, giving 1 as the result so the loop prints one element only.

Pass the number of elements as an argument to the printArr() function.

Note:

• free() what you have malloc()d.
• casting return value of malloc() is unnecessary.
• check return value of scanf() to ensure successful.