Using if and else¶
Most professional programmers would write the following code:
Like this:
An else
is an additional optional phrase on an if
statement. IF AND
ONLY IF the test in the if
is false does the block of statements
after the else
get executed. Using an if
with an else
makes sure
that either the if
block is executed or the else
block is executed,
but never both.
Mixed up programs
csp-12-7-2: csp-12-7-1: The following program should print out "x is even" if the remainder of x
divided by 2 is 0 and "x is odd" otherwise, but the code is mixed up. The
``%`` symbol gives the remainder after the first number is divided by the
second number. Drag the blocks from the left and place them in the correct
order on the right. Be sure to also indent correctly! Click on Check
Me to see if you are right. You will be told if any of the lines are in
the wrong order or have the wrong indention.x = 92
if x % 2 == 0:
print("x is even")
else:
print("x is odd")
It is easy to write an if
when you want exactly one block to execute, but
you can accidentally create a “hole” – a condition where neither block
executes. That’s what happened in the example below when the weight is equal
to 1 pound.
Fix the example above such that the cost of frozen yogurt is 0 if you pour exactly 1 lb. in your cup.