CS1109 LAB 3July 3rd

ROAD MAP Homework submission Review How to use function and scripts While-end Finish last exercise Lab 2 Challenge questions

HOMEWORK SUBMISSION Zip files saving and submitting File name File location Homework 1 questions

LAST WEEK Logic operator

== && || ~= >= <=

Built in function rand fix, floor, ceil disp, fprintf

REVIEW EXERCISE Compute without using Matlab

(~0 & 0)||(0&0) ((~1 || 0)& (0&0))||(1&0) (~(0& 1))||(1&1) suppose a = 1, b = 3

if a>1 & b+a>2a = 3

else a= 4

endQuestion: a+b = ?

REVIEW EXERCISE suppose a = 1, b = 3

if a>1 & b+a>2a = 3;

elseif a> -1a= 4;

elsea = 5;

endQuestion: a+b = ?

REVIEW EXERCISE suppose a = 1, b = 3

if a>-1 & b+a>2a = 3;

elseif a> -1a= 4;

elsea = 5;

endQuestion: a+b = ?

DOUBLE INEQUALITY Type in MATLAB z=6 4<=z<=5

DOUBLE INEQUALITY Type in MATLAB

z=6 4<=z<=5

Something is wrong. If z = 6 then 4<=z<=5 is false. Let's figure out what went wrong later.

First, design a logical statement which will give the right result.

How many ways can you write it?

DOUBLE INEQUALITY

DOUBLE INEQUALITY z<= 5 && z>=4 z<=5 & z>=4 4 <=z && z<=5 4<=z && 5>= z

THIS WEEK Scrip and Function If statement While loop For loop Array

HOW TO USE FUNCTION AND SCRIPTS function out_var=my function(inp_var)

% Comments that explain what the function does computations

out_var=desired result; End

Exercise 1: Try to create a function that adds two numbers The function is called addtwo.m Input: x, y Output: z

function z=addtwo(x,y)% addtwo(x,y) Adds two numbers, vectors,

whatever,% and output the result = x + yz=x+y;

end

SCRIPT Scripts are the simplest kind of program file

because they have no input or output arguments.

Useful for automating series of commands, such as computations that you have to perform repeatedly from the command line.

Exercise 2: Create a script that asks the user to input

two numbers, then add the two numbers and output the sum.

EXERCISE 4 Create a function called new_abs.m which

computes the absolute value of x Input: x Output: y (y =|x|)

EXERCISE 4function y=new_abs(x)

if x>=0y=x;

elsey=-x;

endend

Can you make the above code shorter?

WHILEwhile logical condition

do somethingend

While loop repeats an indefinite number of times until the logical condition matched.

Exercise:Sum 1 to 100Sum 1 to 100, only the numbers that are divisible

by 3

CHALLENGE QUESTIONS

Write a while loop that generates random integer numbers between 1 and 5 and stops looping after it generates the same number twice.

Write a while loop that generates random integer numbers between 1 and 100 and stops looping after it generates the same number twice. (Use array)