Python

OPERATING SYSTEMS LABORATORY RECORD

2. Write a program that displays all three digit numbers that are equal to the sum of the cubes of their digits. These are called Armstrong numbers.

AIM:

ALGORITHM:

CODE:

i = 100while i < 1000: n = i a = n % 10 n = n / 10 b = n % 10 n = n / 10 c = n % 10 n = n / 10 if a ** 3 + b ** 3 + c ** 3 == i: print i i = i + 1

OUTPUT:

153370371

407

3. Write a program to accept a 4-digit number and display the progression to Kaprekar’s constant.

AIM:

ALGORITHM:

CODE:

n = input()

def swap(a,b):t = aa = bb = t

def kaprekar(n,count):

N = na = n % 10n = n / 10

b = n % 10n = n / 10

c = n % 10n = n / 10

d = n % 10n = n / 10

if(a == b and b == c and c == d):print " All digits are same"exit()

i = 1while i <= 5:

if a > b:t = aa = bb = t

if b > c:t = bb = cc = t

if c > d:t = cc = dd = t

i = i + 1

A = 0D = 0

A = 1000 * a + 100 * b + 10 * c + dD = 1000 * d + 100 * c + 10 * b + a

D = D - Aif D == N:

print count

else:kaprekar(D,count + 1)

count = 0kaprekar(n,0)

INPUT: 3524

OUTPUT:

5432 – 2345 = 30878730 – 0378 = 8352

8532 – 2358 = 6174

4. Write a program that generates a list of all four digit numbers that have all their digits even and are perfect squares. For example, the output should include 6400 but not 8100 (one digit is odd) or 4248 (not a perfect square).

AIM:

ALGORITHM:

i = 32while i < 100: n = i * i Flag = True while Flag and n > 0: d = n % 10 if d % 2 == 1: Flag = False n = n / 10 if Flag is True: print i ** 2 i = i + 1

OUTPUT:

4624

6084

6400

8464

5. The aliquot of a number is defined as: the sum of the proper of the number.For example, the aliquot(12) = 1 + 2 + 3 + 4 + 6 = 16.Write a function that returns the aliquot number of a given number.

AIM:

ALGORITHM:

CODE:

n = input()

i = 1sum = 0

while i * i < n:if n % i == 0:

sum = sum + isum = sum + n / i

i = i + 1

if i * i == n:sum = sum + i

sum = sum - nprint sum

INPUT: 1234

OUTPUT: 620

6. A pair of numbers (a, b) is said to be amicable if the aliquot number of a is b and the aliquot number of b is a.

AIM:

ALGORITHM:

CODE:

def aliquot(n):sum = 0i = 1while i * i < n:

if n % i == 0:

sum = sum + isum = sum + n / i

i = i + 1

if i * i == n:sum = sum + i

sum = sum - nreturn sum

a = 1list = [0]empty = []i = 1

while a < 100000:list.append(aliquot(a))a = a + 1

i = 1while i < 100000:

if list[i] < 100000 and list[i] > 0 and i == list[list[i]] and i < list[i]:

print i,list[i]i = i + 1

OUTPUT:

220 284

1184 1210

2620 2924

5020 5564

6232 6368

10744 10856

12285 14595

17296 18416

63020 76084

66928 66992

67095 71145

69615 87633

79750 88730

7. Write a program to display the following pyramid. The number of lines has to be a parameterobtained from the user. The pyramid must appear aligned to the left edge of the screen.12 43 6 94 8 12 165 10 15 20 25

AIM:

ALGORITHM:

CODE:

n = input()

i = 1while i <= n:

list = []j = 1while j <= i:

list.append(i * j)j = j + 1

s = ''for k in list:

s = s + str(k) + ' 'print s

i = i + 1

OUTPUT:

12 43 6 94 8 12 165 10 15 20

8. Given a string of the form "4-7, 9, 12, 15" find the numbers missing in this list for a given range.

AIM:

ALGORITHM:

CODE:

s = raw_input()

list = s.split(',')final = []

print list

i = 0while i < len(list):

list[i] = list[i].strip()i = i + 1

for i in list:temp = itemp = temp.split('-')if len(temp) == 1:

final.append(int(temp[0]))else:

start = int(temp[0])end = int(temp[1])j = startwhile j <= end:

final.append(j)j = j + 1

INPUT: 1, 2-7, 10-12, 16-19, 18-24

OUTPUT: ['1', ' 2-7', ' 10-12', ' 16-19', ' 18-24']

9. Round Robin scheduling

AIM:

ALGORITHM:

CODE:

print " Enter total processes- "

n = input()

process = []sum = 0

print " Enter the burst times of processes- "

i = 0while i < n:

process.append([])a = input()process[i].append(a)sum = sum + ai = i + 1

print " Enter arrival times of processes one by one- "

i = 0while i < n:

a = input()process[i].append(a)process[i].append(i)i = i + 1

print " Enter time slice "s = input()

t = []i = 0while i < 100:

t.append(-1)i = i + 1

cur = 0idx = -1while len(process) > 0:

idx = (idx + 1) % len(process)while cur < process[idx][1]:

idx = (idx + 1) % len(process)m = min( process[idx][0], s )#print idx,mi = 0while i < m:

t[cur + i] = process[idx][2] + 1i = i + 1

cur = cur + mprocess[idx][0] = process[idx][0] - mif process[idx][0] == 0:

del process[idx]idx = (idx - 1)if idx < 0:

idx = len(process) - 1

cur = 0print "Time Process ID "while t[cur] != -1:

start = curidx = t[cur]while t[cur] == idx:

cur = cur + 1print start," - ",cur," ", idx

INPUT:

Enter total processors- 3

Enter burst times sone by one- 2 4 10

Enter arrival times one by one- 0 1 2

Enter time slice- 3

OUTPUT:

Time Process ID

0 - 2 1

2 - 5 2

5 - 8 3

8 - 9 2

9 - 16 3

10.SJF scheduling

AIM:

ALGORITHM:

CODE:print " Enter total processes- "

n = input()

process = []


i = 0while i < n:

process.append([])a = input()process[i].append(a)i = i + 1


i = 0while i < n:


t = []i = 0while i < 100:


process.sort()

i = 0

while i < n:idx = process[i][2]cur = process[i][1]burst = process[i][0]while burst > 0:

if t[cur] == -1:t[cur] = idx + 1burst = burst - 1

cur = cur + 1i = i + 1




INPUT:

Enter total processes- 3

Enter the burst times of processes- 2 4 10

Enter arrival times of processes one by one- 0 1 2

OUTPUT:

Time Process ID

0 - 2 1

2 - 6 2

6 - 16 3

11.SRTF scheduling

AIM:

ALGORITHM:

CODE:print " Enter total processes- "

n = input()

process = []


i = 0while i < n:

process.append([])a = input()process[i].append(a)i = i + 1


i = 0while i < n:


t = []i = 0while i < 100:


process.sort()

i = 0while i < n:

idx = process[i][2]cur = process[i][1]burst = process[i][0]while burst > 0:

if t[cur] == -1:t[cur] = idx + 1burst = burst - 1

cur = cur + 1i = i + 1




INPUT:


Enter the burst times of processes- 2 4 10

Enter arrival times of processes one by one- 0 1 2

OUTPUT:

Time Process ID

0 - 2 1

2 - 6 2

6 - 16 3

12.FIRST FIT MEMORY PARTITIONING

AIM:

ALGORITHM:

CODE:

print "Enter total partitions- "n = input()

p = []flag = []process = []M = []

print "Enter partition sizes one by one- "for i in range(n): a = input() p.append(a) flag.append(False)

print "Enter total processes- "N = input()

print "Enter process sizes one by one"for i in range(N): a = input() process.append(a)

i = 0while i < N: print process[i] i = i + 1

#First fit

i = 0while i < N: c = process[i] j = 0 while j < n: if p[j] >= c and flag[j] is False: flag[j] = True M[i] = j break j = j + 1 i = i + 1

i = 0while i < N: print "Process ", i, " allocated to partition of size ", p[M[i]] i = i + 1

INPUT:

Enter total partitions- 6

Enter partition sizes one by one- 400 300 200 500 600 600


Enter process sizes one by one- 212 314 545 416 276

OUTPUT:

First Fit:

Process 0 allocated to partition of size 400





Memory wasted in partition of size 400 is 188






13.BEST FIT MEMORY PARTITIONING

AIM:

ALGORITHM:

CODE:


p = []flag = []process = []

M = []Wastage = []

print "Enter partition sizes one by one- "for i in range(n): a = input() p.append(a) flag.append(False) Wastage.append(a)


print "Enter process sizes one by one"for i in range(N): a = input() process.append(a) M.append(-1)

i = 0while i < n: print p[i] i = i + 1

print " "


#Best fit

print " "print "Best Fit:"

i = 0while i < N: c = process[i] best = 1000000 M[i] = -1 j = 0 while j < n: if p[j] >= c and flag[j] is False and p[j] - c < best: M[i] = j best = p[j] - c j = j + 1 flag[M[i]] = True Wastage[M[i]] = p[M[i]] - c i = i + 1

i = 0while i < N: if M[i] == -1: print "Process ",i," not allocated to any partition " else:

print "Process ", i, " allocated to partition of size ", p[M[i]] i = i + 1

sum = 0print " "i = 0while i < n: print "Memory wasted in partition of size ", p[i], " is ", Wastage[i] sum = sum + Wastage[i] i = i + 1

print "\nTotal wastage: ", sum

INPUT:





OUTPUT:

Best Fit:












Total wastage: 837

14.WORST FIT MEMORY PARTITIONING

AIM:

ALGORITHM:

CODE:


p = []flag = []process = []M = []Wastage = []

print "Enter partition sizes one by one- "for i in range(n): a = input() p.append(a)

flag.append(False) Wastage.append(a)


print "Enter process sizes one by one"for i in range(N): a = input() process.append(a) M.append(-1)

i = 0while i < n: print p[i] i = i + 1

print " "


#Worst fit

print " "print "First Fit:"

i = 0while i < N: c = process[i] M[i] = -1 j = 0 worst = 0 while j < n: if flag[j] is False and p[j] > p[worst]: worst = j j = j + 1 if p[worst] >= c: M[i] = worst Wastage[worst] = p[worst] - c flag[worst] = True i = i + 1

i = 0while i < N: if M[i] == -1: print "Process ",i," not allocated to any partition " else: print "Process ", i, " allocated to partition of size ", p[M[i]] i = i + 1

sum = 0print " "i = 0while i < n: print "Memory wasted in partition of size ", p[i], " is ", Wastage[i] sum = sum + Wastage[i] i = i + 1

print "\nTotal wastage: ", sum

INPUT:





OUTPUT:

First Fit:



Process 2 not allocated to any partition









Total wastage: 1382

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