Give an explanation, in complete English sentences, of the following concepts in C code. The explanation should be sufficient for a classmate to understand the concept, even if they had not previously been exposed to it.

3) Suppose i is an int variable, and p and q are type pointer to int variables. For each expression, either explain what the given statement accomplishes, or indicate that the given statement is illegal, and why.

(a) p = &i;

(b) *p = i;

(c) *q = &i;

(d) p = q;

4) Explain what is wrong with the following function.

//This function takes in two integer pointers as parameters, and //swaps them.

void swap(int *x, int *y) {

int *t = x;

x = y;

y = t;

}

5) At the end of the following snippet of code, indicate how many bytes of dynamically-allocated memory are allocated to the program, and which pointers can safely be dereferenced. Assume that sizeof(int) is 4 bytes, and no allocation failures occur.

int size = 10;

int *a = malloc(size * sizeof(int));

int *b = realloc(a, size * 2 * sizeof(int));

6) Given the following struct:

struct data {

char *s;

double *t;

};

And assuming:

Pointers and doubles take 8 bytes each

Chars take 1 byte each

The struct is not "padded"

Describe how much memory is leaked by the following code, and suggest code to insert (including where it should be inserted) to fix the memory leak(s).

struct data *d = (struct data*)malloc(sizeof(struct data));

d->s = (char*)malloc(4 * sizeof(char) + 1);

d->t = (double*)malloc(4 * sizeof(double));

// (code using d)

free(d);