5 replies to this topic

[bbqroast]

The code below calculates the area of a triangle. Sadly it only returns whole numbers (no decimal points!).

from time import sleep

h = input("Enter the height of the triangle (cm): ")

w = input("Enter the base of the triangle (cm): ")

print "Height =",

print h

print "Width =",

print w

area = (w * h)

area = area/2

print "The area of the triangle is =",

print area,

print "cm2"

print "This program will close in 10 Seconds"

sleep(10)

I have worked out I need to make "area" a float type variable. Sadly unlike C++ I don't know how to define this. I have looked in the user guide and can find no references to this.

Thanks in Advanced
bbqroast

[Alexander]

Are you sure it is returning a whole number?

root@linux:~$python bbqroast.py 
Enter the height of the triangle (cm): 2.2
Enter the base of the triangle (cm): 3.4
Height = 2.2
Width = 3.4
The area of the triangle is = 3.74 cm2
This program will close in 10 Seconds

Try giving us an example output.

[Flying Dutchman]

The easiet way is to just add dot to number 2 where you are dividing. Or you can explicitly convert to float with float() function (it's actually a class constructor to be precise).

[bbqroast]

Hmmph maybe python returns decimals only when you start with them.
E.g.

Enter the height of the triangle (cm): 3

Enter the base of the triangle (cm): 3

Height = 3

Width = 3

The area of the triangle is = 4 cm2

This program will close in 10 Seconds

Look at this

Enter the height of the triangle (cm): 3.0

Enter the base of the triangle (cm): 3.0

Height = 3.0

Width = 3.0

The area of the triangle is = 4.5 cm2

This program will close in 10 Seconds

If all else fails I could just check to see if their is a decimal point:
If not add a .0 in the end.
If their is just continue on.

Edited by bbqroast, 08 February 2011 - 10:31 PM.
Tested idea

[restored]

from time import sleep

timeout = 10

h = input("Enter the height of the triangle (cm): ")

w = input("Enter the base of the triangle (cm): ")

h, w = float(h), float(w)

print "Height = %g" % h

print "Width = %g" % w

area = w * h / 2

print "The area of the triangle is = %g %s" % (area, "cm2")

print "This program will close in %d Seconds" % timeout

sleep(timeout)

output

[guest@localhost tests]$ python2.6 t2.py

Enter the height of the triangle (cm): 3.2

Enter the base of the triangle (cm): 4

Height = 3.2

Width = 4

The area of the triangle is = 6.4 cm2

This program will close in 10 Seconds

[guest@localhost tests]$

" %s %s " % ('abc', 'def')
is an old form of string formatting

[Flying Dutchman]

area = (w * h)

area = area/2

Instead of this, you could write

area = (w * h) / 2.0

and it will cast area to float.