Pointers as Function Parameters¶

Call by Reference (1)¶

Problem: in C, parameters are passed by-copy* - callee see *copies of the caller’s values.
Question: how can I use a function to modify the caller’s value?

void f(int a)
{
    a = 42;
}

void main(void)
{
    int i = 1;

    f(i);
    /* i is still 1 */
}

Solution: pointer

void f(int *a)
{
    *a = 42;
}

void main(void)
{
    int i = 1;

    f(&i);
}

A sketch of that matter (made on a Wacom-tablet during one course)¶