def rev(s):
st = []
top = 0
for i in s:
top = m.push(st, i, top)
#print('top =',top)
rev = []
top1 = None
for i in range(top + 1):
top, e = m.pull(st, top)
top1 = m.push(rev, e, top1)
#print(''.join(rev))
#print('top1=',top1)
return ''.join(rev)
'''3. Imagine that you are writing a program for a simple text editor. Using stacks how would you implement the undo and redo options?
[consider a list as the text. Undo is the
deletion of the latest character into the text and redo is pushing it back in].'''
import mods as m
st = []
u = []
topu = 0
top = 0
flag = 0
#print('welcome to text editor!( enter < and press enter to undo or enter > and press enter to redo OR just press enter to exit)')
while True:
n = input()
for i in n:
top = m.push(st, i, top)
top, i = m.pull(st, top)
#if i == '\n':
#print('ahhhhhh')
#top,e = m.pull(st,top)
#topu = m.push(u,e,topu)
#flag = 1
if i == '<':
if top == None:
print('cannot undo')
else:
top, e = m.pull(st, top)
topu = m.push(u, e, topu)
flag = 1
elif i == '>':
if flag == 1:
topu, e = m.pull(u, topu)
top = m.push(st, e, top)
import mods as m
st = []
top = 0
top = m.push(st,8,top)
print(st)
print(top)
top = m.push(st,9,top)
print(st)
print(top)
top,poop = m.pull(st,top)
print(st)
print(top)
print('poop=',poop)
#2. Import the file into another program, send a string in the form of a stack. Reverse the string using pop.
#3. Using the same file convert a decimal number into its binary equivalent using the stack functionality
import mods as m
#s = 'hellooo'
def rev(s):
st = []
top = 0
for i in s:
top = m.push(st, i, top)
#print('top =',top)
rev = []
top1 = None
for i in range(top + 1):
top, e = m.pull(st, top)
top1 = m.push(rev, e, top1)
#print(''.join(rev))
#print('top1=',top1)
return ''.join(rev)
st1 = []
top2 = 0
n = int(input('enter number'))
while n >= 1:
top2 = m.push(st1, str(n % 2), top2)
n = n // 2
print(st1)
print(rev(''.join(st1)))
d = {"0": 0, "/": 4, "*": 3, "+": 2, "-": 1}
l1 = []
top = len(l1)
print(top)
for a in l:
if a not in (
"-", "+", "*", "/", "(", ")"
): #(ord(a)>=65 and ord(a)<=90) or (ord(a)>=97 and ord(a)<=122)or(a=="1" or "2" or"3"or"4"or"5"or"6"or"7"or"8"or"9"):
print(a, end="")
if a in ("-", "+", "*", "/"):
print('t', top)
while (top != 0) and (d[a] <= d[l1[top - 1]]) and (l1[top - 1] != "("):
p = stacks.pull(l1, top)
top = len(l1)
print(p[1], end="")
m.push(l1, a, top)
top = len(l1)
if a == "(":
m.push(l1, a, top)
top = len(l1)
if a == ")":
while l1[top] != "(":
m = m.pull(l1)
print(m[1], end="")
l = m.pull(l1)
print(top)
while top != 0:
x = stacks.pop(l1)
print(x[1])