CSC231 Powers of 2 in Python

Back to Weekly Schedule

---

--D. Thiebaut 13:57, 8 October 2010 (UTC)

---

This Exercise is a companion to the same exercise implemented in C++.

Exercise: A Python Program that loops forever...

• First do the exercise with C++ mentioned above.
• Then create the program below, and run it. It will wait you to press Enter at every loop, so that you can control the speed of the loop.
• What happens when you reach 2147483648, and press Enter a few times? How is that different from the C++ approach? Why?

The Program

# mulby2.py
# D. Thiebaut
# csc231
# demonstrates how python changes type of
# variable as computation progresses.  Compare 
# this to how a compiled language would react in this
# situation (mulby2.cpp)

x = 0x1
print "starting value of x = ", x

#curType = type( x )
#print "type( x ) = ", type( x )

while ( True ):
    lastx = x
    x = x * 2
    print "x = ", x
    raw_input(  "> " )
    continue

    if type( x )!= type( lastx ):
        print "last x = ", lastx
        print "type( last x ) = ", type( lastx ) 
        print "x = ", x
        print "type( x ) = ", type(x)
        break