[Solved] inner product function in C [closed]

You have so many errors in your code. First, you are not defining your arrays as arrays, but as single int values. You should define them correctly:

int *a, *b;

Second, you are not allocating your arrays. If you want to create them on runtime you will have to use malloc() after you get the size for them:

a = (int*)malloc(sizeof(int) * n);
b = (int*)malloc(sizeof(int) * n);

Third, it is not necessary to pass your array values as reference, because you will not need to modify them:

printf("%d", inner_product(a, b, n));

Inside your inner_product() function:

&(a + i) and &(b + i) won’t give you the memory position of the array item (because it depends on the memory block size). You should use &a[i] and &b[i] instead to get the array values.

Because your variables a and b are arrays, your inner product should be calculated this way:

for (i = 0; i < size; ++i)
    sum += a[i] * b[i];

Tip: be sure to freeing your allocated a and b arrays by calling free(a) and free(b) after calling inner_product().

That’s it!