1. Elements of Programming


Our goal in this chapter is to convince you that composing a computer program is easier than writing a piece of text such as a paragraph or an essay. Writing prose is difficult: we spend many years in school to learn how to do it. By contrast, just a few building blocks suffice to take us into a world where we can harness the computer to help us solve all sorts of fascinating problems that would be otherwise unapproachable. In this chapter, we take you through these building blocks, get you started on programming in Python, and study a variety of interesting programs.

Python Programs in this Chapter

Below is a list of Python programs and data files used in this chapter.

REF PROGRAM DESCRIPTION DATA
1.1.1 helloworld.py Hello, World
1.1.2 useargument.py using a command-line argument
1.2.1 ruler.py string concatenation example
1.2.2 intops.py integer operators
1.2.3 floatops.py float operators
1.2.4 quadratic.py quadratic formula
1.2.5 leapyear.py leap year
1.3.1 flip.py flipping a fair coin
1.3.2 tenhellos.py your first loop
1.3.3 powersoftwo.py computing powers of two
1.3.4 divisorpattern.py your first nested loops
1.3.5 harmonic.py harmonic numbers
1.3.6 sqrt.py Newton's method
1.3.7 binary.py converting to binary
1.3.8 gambler.py gambler's ruin simulation
1.3.9 factors.py factoring integers
1.4.1 sample.py sampling without replacement
1.4.2 couponcollector.py coupon collector simulation
1.4.3 primesieve.py sieve of Eratosthenes
1.4.4 selfavoid.py self-avoiding random walks
1.5.1 randomseq.py generating a random sequence
1.5.2 twentyquestions.py interactive user input
1.5.3 average.py averaging a stream of numbers
1.5.4 rangefilter.py a simple filter
1.5.5 plotfilter.py standard input to draw filter usa.txt  
1.5.6 bouncingball.py bouncing ball
1.5.7 playthattune.py digital signal processing elise.txt  ascale.txt  stairwaytoheaven.txt  entertainer.txt  firstcut.txt  freebird.txt  looney.txt  
1.6.1 transition.py computing the transition matrix tiny.txt  medium.txt  
1.6.2 randomsurfer.py simulating a random surfer
1.6.3 markov.py mixing a Markov chain