Arrays and Pointers

#Tutorial14#

In a previous tutorial on Pointers, you learned that a pointer to a given data type can store the address of any variable of that particular data type. For example, in the following code, the pointer variable pc stores the address of the character variable c.

char c = 'A';
char *pc = &c;

Execute Code Here, c is a scalar variable that can store only a single value. However, you are already familiar with arrays that can hold multiple values of the same data type in a contiguously allocated memory block. So, you might wonder, can we have pointers to arrays too? Indeed, we can.
Let us start with an example code and look at its output. We will discuss its behavior subsequently.

char vowels[] = {'A', 'E', 'I', 'O', 'U'};
char *pvowels = &vowels;
int i;

// Print the addresses
for (i = 0; i < 5; i++) {
    printf("&vowels[%d]: %u, pvowels + %d: %u, vowels + %d: %u\n", i, &vowels[i], i, pvowels + i, i, vowels + i);
}

// Print the values
for (i = 0; i < 5; i++) {
    printf("vowels[%d]: %c, *(pvowels + %d): %c, *(vowels + %d): %c\n", i, vowels[i], i, *(pvowels + i), i, *(vowels + i));
}

Execute Code A typical output of the above code is shown below.

&vowels[0]: 4287605531, pvowels + 0: 4287605531, vowels + 0: 4287605531
&vowels[1]: 4287605532, pvowels + 1: 4287605532, vowels + 1: 4287605532
&vowels[2]: 4287605533, pvowels + 2: 4287605533, vowels + 2: 4287605533
&vowels[3]: 4287605534, pvowels + 3: 4287605534, vowels + 3: 4287605534
&vowels[4]: 4287605535, pvowels + 4: 4287605535, vowels + 4: 4287605535
vowels[0]: A, *(pvowels + 0): A, *(vowels + 0): A
vowels[1]: E, *(pvowels + 1): E, *(vowels + 1): E
vowels[2]: I, *(pvowels + 2): I, *(vowels + 2): I
vowels[3]: O, *(pvowels + 3): O, *(vowels + 3): O
vowels[4]: U, *(pvowels + 4): U, *(vowels + 4): U