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 = 3if a>1 & b+a>2
a = 3;elseif a> -1
a= 4;else
a = 5;end
Question: a+b = ?
REVIEW EXERCISE
suppose a = 1, b = 3if a>-1 & b+a>2
a = 3;elseif a> -1
a= 4;else
a = 5;end
Question: 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
computationsout_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 4
function y=new_abs(x)if x>=0
y=x;
elsey=-x;
end
end
Can you make the above code shorter?
WHILE
while logical condition do something
end
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)