# See extensive tutorial here https://docs.python.org/3/library/sqlite3.html
import sqlite3
con = sqlite3.connect("bank.db", autocommit=True)

cur = con.cursor()

print()

print("Running a SELECT query:")
res = cur.execute("SELECT * FROM acc")
answ = res.fetchall()
print("The answer is: ", answ)

print()  # comment here
print("Running an UPDATE query:")
# everyone gets an interest of 4%
for row in answ:
    usr = row[0]
    bal = row[1]
    b = int(bal)
    i = b*0.04
    print("User "+usr+" has an interest of "+str(i))
    print("Upating the balance")
    cur.execute("UPDATE acc SET balance=? WHERE usr=?", [b+i, usr])

print()

print("Running the SELECT query again:")
res = cur.execute("SELECT * FROM acc")
answ = res.fetchall()
print("The answer is: ", answ)