Question

Please help:)
Show the state of the stack and the value of each variable after execution of each of the following statements:
p=2.5 q=3.30 r=7.003 d=0.00026

create stack
push q onto stack
push d onto stack
pop item from stack
push r onto stack
push p onto stack
p=q*r
push p+r+d onto stack
pop item from stack and store in p
pop item from stack and store in q
pop item from stack and store in r

Answer 1

Create Stack: *bzzt*
Push q onto stack, stack becomes [q]
Push d onto stack, stack becomes [q, d]
pop item from stack, stack becomes [d]
push r onto stack, stack becomes [d, r]
push p onto stack, stack becomes [d. r. p]
p=q*r, stack becomes [d, r, q*r]
push p+r+d onto stack, stack becomes [d, r, q*r, p+r+d]
pop item from stack and store in p, p becomes d
pop item from stack and store in q. q becomes r
pop item from stack and store in r, r becomes q*r.

Answer 2

^That is wrong.

Answer 3

create stack
push q onto stack[q]
push d onto stack[q,d]
pop item from stack[q]
push r onto stack[q,r]
push p onto stack[q,r,p]
p=q*r // do nothing
push p+r+d onto stack[q, r, p, (p[q * r]+r+d)]
pop item from stack and store in p [q,r,p] // (p[q * r]+r+d)] = p
pop item from stack and store in q [q,r] // p = q
pop item from stack and store in r [q] // r = r

Answer 4

@KonradZuse Can u please explain me the line
push p+r+d onto stack[q, r, p, (p[q * r]+r+d)]
Why it is p[q*r]? I dnt get that part.

Answer 5

I meant p = q * r, syntax fail on my part.

Answer 6

p + r + d or (r*d) + d + r

Answer 7

u mean p+r+d=(q*r)+d+r?

Answer 8

@KonradZuse so it will be
create stack
push q onto stack[q]
push d onto stack[q,d]
pop item from stack[q]
push r onto stack[q,r]
push p onto stack[q,r,p]
p=q*r // do nothing
push p+r+d onto stack[q, r, p, ([q * r]+r+d)]
pop item from stack and store in p [q,r,p] // ([q * r]+r+d)] = p
pop item from stack and store in q [q,r] // p = q
pop item from stack and store in r [q] // r = r. Isn't t?

Answer 9

@KonradZuse D'oh, messed up stacks with queues.

Answer 10

yes remember queues are first in first out(think of a line of school children, or lunch line) then stacks are first in last out, so think of a stack of papers. If you put a papper at the bottom, you need to do all the papers on top of it first to get to that one paper.

Answer 11

not too sure why r = r, but that's how it's supposed to be done.....

Answer 12

oh k. thank u soooo much @KonradZuse

Answer 13

np, goodluck.