ELEMENTS OF PROGRAMMING
Part 3

To understand iteration

To create loops in Python

To create programs with conditional and iteration statements

Iterative statements

The loop mechanism causes repeated execution of a sequence of statements as long as a certain condition is true.

Types of loops:

While loop

initialization

condition

update

Write a program that prints the integer cube root of an integer. If the input is not a perfect cube, it prints a message to that effect.

*Guttag, JV. Introduction to Computation Using Python

We used “guess and check” or exhaustive enumeration as our algorithmic technique.

For loop

can be defined by range, strings*, or lists*.

*We’ll use these for for loops when we get to these topics.

start

stop

step

Write a program that prints the sum of N integers.

What would be the output of the following code? Describe the program.

if-else + loops

Given an integer n, create a program that does a count down (to zero) if the integer is positive and does a count up (to zero) if the integer is negative.

Behavior changing keywords

exits out of the smallest enclosing loop.

terminates the loop and transfers execution to the statement after the loop

forces a loop to loop again, skipping the rest of body

Create a program that produces a random number and makes the user guess that number. Clues are given (higher or lower) to help the user guess the number.

Loop statements may have an clause which is executed when a loop is not terminated by a break.