TRANSCRIPT.md

Basics of C Pointers (Transcript)

What is a pointer, and why are they important?

pointer == memory address pointer variable == variable that holds a memory address

Things pointers make easy:

• Allowing a function to "modify a variable"
• Dynamic memory allocation
• Representation of abstract structures

How do I declare a pointer variable?

int x = 10;
int *p = &x;
printf("p is a memory address. See? %p\n", p);

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int x = 10;
int *p;
p = &x;
printf("p is a memory address. See? %p\n", p);

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int x = 10;
int *p = &x;

// %ld represents a long int for printf
printf("Size of a pointer to int: %ld\n", sizeof(p));
printf("Size of int: %ld\n", sizeof(*p));

What does it mean to 'dereference' a pointer?

"Retrieve the value p is pointing at"
"The value associated with the memory address p"

int x = 10;
int *p = &x;
*p = 20;
printf("The value is: %d\n", *p);

// THIS IS WRONG
int *p;
*p = 10;

How do I handle pointers inside a function?

How can I use pointers with structures?