J78uDhq7

1import pathlib
2import sqlite3
3import threading
4import random
5import time
6
7
8class PetersonSolution():
9    # Check if database exists or not, if not Create a new database
10    file = pathlib.Path("Peter.db")
11    if file.exists():
12        print("File exist")
13        conn = sqlite3.connect('Peter.db')
14        c = conn.cursor()
15        c.execute("SELECT * FROM `security`")
16        conn.commit()
17        for row in c.fetchall():
18            user = row[1]
19            print("user = ", user)
20            break
21    else:
22        print("Creating DB")
23        conn = sqlite3.connect('Peter.db')
24        c = conn.cursor()
25        c.execute("""CREATE TABLE security(Account INTEGER, User string NOT NULL)""")
26        user = input("Enter Username")
27        abc = input("enter account money")
28        c = conn.cursor()
29        c.execute('INSERT INTO security(Account, User) VALUES(?,?)', (abc, user))
30        conn.commit()
31    sel_user = user
32    c = conn.cursor()
33    c.execute("SELECT `Account` FROM `security` WHERE `User` = ?", (sel_user,))
34    conn.commit()
35    for row in c.fetchall():
36        balance = row[0]
37        print("Balance = ", balance)
38        print()
39        break
40    # since we are starting with process 0, the other process would be 1.
41    other = 1
42    turn = 0
43
44    # at the start none of the process is interested in critical section.
45    interested = [False, False]
46
47
48
49    def EntrySection(self, *args):
50        # if process 0 entered other process would be 1 and if process 1 entered other process would be 0.
51        PetersonSolution.other = 1 - args[0]
52        # entered process is intrested, hence True
53        PetersonSolution.interested[args[0]] = True
54
55        # set turn to the entering process
56        PetersonSolution.turn = args[0]
57
58        # if other process is already in the critical section prevent any other process from entering
59        while PetersonSolution.interested[PetersonSolution.other] == True and PetersonSolution.turn == args[0]:
60            if args[0] == 0:
61               # PetersonSolution.balance = PetersonSolution.balance + 10
62                print(f"Process P0 is waiting for Deposit")
63                time.sleep(1)
64            else:
65               # PetersonSolution.balance = PetersonSolution.balance - 10
66                print(f"Process P1 is waiting for Withdrawal")
67
68                time.sleep(1)
69
70
71        # if no process is in critical section then run critical  section
72        conn = sqlite3.connect('Peter.db')
73        if args[0] == 0:
74            print(f"Initial Balance = {PetersonSolution.balance} Rupees")
75            balance = PetersonSolution.balance + 10
76            print(f"Balance after Depositing = {balance} Rupees")
77            c = conn.cursor()
78            c.execute('UPDATE security SET `Account` = ? WHERE `Account` = ?', (balance, PetersonSolution.balance))
79            conn.commit()
80            #c.close()
81
82        else:
83            print(f"Initail Balance = {PetersonSolution.balance} Rupees")
84            balance = PetersonSolution.balance - 10
85            print(f"Balance After Withdrawing = {balance} Rupees")
86            c = conn.cursor()
87            c.execute('UPDATE security SET `Account` = ? WHERE `Account` = ?', (balance, PetersonSolution.balance))
88            conn.commit()
89
90        self.ExitSection(args[0])
91        time.sleep(3000)
92
93
94    def ExitSection(self, process):
95        # process finished executing, make interested for the process as False
96        PetersonSolution.interested[process] = False
97
98    def main(self):
99        p = 50
100        while p > 1:
101            # start process 0, passing process index 0 as args since Thread supports args and kwargs argument only
102            t1 = threading.Thread(target=self.EntrySection, args=(0,))
103            t1.start()
104            # start process 1,passing process index 1 as args
105            t2 = threading.Thread(target=self.EntrySection, args=(1,))
106            t2.start()
107            #time.sleep(0.1)
108            p = p - 1
109            print("iteration = ", p)
110
111
112
113if __name__ == "__main__":
114    p = PetersonSolution()
115    p.main()
116
117    #i = 3000
118    #i = i + 10