Week 5 - Friday

 What did we talk about last time?  Repetition  while loops

while( condition ) { statement1; statement2; … statementn; } A whole bunch of statements

 Let’s say that you wanted to write a program to guess a number that a person had come up with  The number is between 1 and 100  Every time the computer guesses a number, the person enters:  H if the number is too high  L if the number is too low  F if the number was found

1. Start with the minimum and maximum of the range 2. Find the midpoint 3. Ask the user if the midpoint is correct 4. If the answer is too high, go to Step 1 using the minimum and the midpoint - 1 as the new range 5. If the answer is too low, go to Step 1 using the midpoint + 1 and the maximum as the new range 6. If the midpoint is correct, you’re done!

 Just as with if -statements, it’s possible to nest loops  A repetitive task can be done inside of another repetitive task  Be careful! You can make the computer do a lot of work

 Triangular numbers are 1, 3, 6, 10, …  1 = 1  3 =  6 =   Let’s write a program that expresses the n th triangular number by printing 1 on the first line, 1 and 2 on the second line, 1, 2, and 3 on the third line, and so on

 for loops  More loop examples

 Keep reading Chapter 5  Keep working on Project 2