cs 50 memory lecture

Question 1

what is added arbitrarily to the beginning of hex values to signify that it is a hex value?

Answer 1

0x
example:
0x
0xC

Question 2

what is this value in hexadecimal 10

Answer 2

16
why?
because we count from 0 - f (which is 15) in the first most right value. once we hit the highest value (which is f) we put a 1 next to the right value which signifies the 16th place. like counting in base 10 but instead we use base 16

Question 3

what is a pointer?

Answer 3

an address in the computer’s memory

Question 4

what is a string when thinking about it in terms of memory in c

Answer 4

it is a pointer to the first character. the rest of the characters will follow that address

Question 5

when you print a string to the screen, how does the computer know where to stop in memory?

Answer 5

each string has a null terminating character at the end of it in memory. when the computer sees that null terminating string it stops.
/0 is added to every string to show that the memory address ends with the null terminating character

Question 6

How is memory organized physically? where is the machine code, globals, heap and stack

Answer 6

machine code
globals
heap (chunk of memory you can allocate from) 
 ↓
 ↑
stack (runs your functions)