Difference between revisions of "KTurtle/C3/Common-Errors-in-KTurtle/English"

Welcome to this tutorial on Common Errors in KTurtle.

Learning Objectives

• Syntax errors and

• Runtime errors

System Requirement

Ubuntu Linux OS v. 12.04. KTurtle v. 0.8.1 beta.

Pre-requisites

If not, for relevant tutorials, please visit our website. http://spoken-tutorial.org

Syntax Errors

Compilation fails when a program has syntax errors.

Syntax errors are easy to find and fix.

For Example:

• Unmatched parentheses, square brackets and curly braces.

• Use of variable that has not been declared.

• Missing quotes in strings.

Dash home >>Search bar appears>> In the Search bar type KTurtle Click on the KTurtle icon.

Click on Dash home. The Search bar appears.

In the Search bar, type KTurtle.

Click on the KTurtle icon.

$a=ask "enter any number and click Ok"

$r = ask "enter any number and click ok"

$n = ask "enter any number and click ok"

$T = $a*($r^$n)*($r^-1)

print $T

Please pause the tutorial and type the program into KTurtle editor

Resume the tutorial after typing the program.

It may possibly be a little blurred.

$a=ask "enter any number and click Ok"

Complier shows the following error,

The variable "$a" was used without first being assigned to a value.

press F5 key to run the program

We see that the program runs without errors.

$degree=ask "enter any angle value and click OK"

$radian=(pi/180)*$degree

go 50,50

print "Value in radians is"+ " " +$radian

spritehide

Please pause the tutorial and type the program into KTurtle editor

Resume the tutorial after typing the program.

It may possibly be a little blurred.

Run the program

Complier shows the following error,

you cannot put “=” here

Program runs properly

Complier shows the following error,

text string was not properly closed, expected a double quote “ ” to close the string.

press F5 key run the program.

program runs without errors.

Runtime errors

It may crash the program when you run it.

Runtime errors are commonly due to wrong input from the user.

Compiler cannnot find these errors.

For example:

• Trying to multiply or divide by a variable that contains no value.

• Run a loop without a condition or increment.

$C= ask "enter any number in celsius scale and click OK"

message "$F is Fahrenheit"

$F=(9/5*$C)+32

go 40,40

print "Value in Fahrenheit =" +" "+ $F+"F"

Please pause the tutorial and type the program into KTurtle editor

Resume the tutorial after typing the program.

It may possibly be a little blurred.

Complier does not shows any error.

Here we get an error as the program runs.

The print command was called with 0 but it needs 1 parameter.

It is a runtime error.

program runs without runtime errors.

reset

$x=0

message"In while loop, code inside the loop repeats till boolean evaluates false"

while $x<20 {

$x=$x+2

$x=$x*1

fontsize 15

forward 20

print $x }

Please pause the tutorial and type the program into KTurtle editor

Resume the tutorial after typing the program.

It may possibly be a little blurred.

Complier does not show any error.

We get a runtime error.

Loop become an infinite loop of zeros.

program runs properly as expected.

$x=8

$r = 1

for $i = 1 to $x {

$r = $r * $i

forward 20

print $r }

Please pause the tutorial and type the program into KTurtle editor

Resume the tutorial after typing the program.

It may possibly be a little blurred.

Complier does not show any error.

We get a runtime error.

We see that only the Turtle has moved forward.

“for” loop is not executed.

Program runs properly as expected.

let us summarise.

Summary

• Use of variable that has not been declared.

• Missing quotes in strings.

• Errors related to print command

• Runtime errors

Assignment

$x=3

$y=3

if $x==$y

print"they are equal"

else {

print "they are not equal"}

reset

$x=ask "enter value for x and click Ok"

$y = ask "enter value for y and click Ok"

$g =sqrt ($x*$y)

print "Geometric mean is ="+

learn sum $x {

{$r=0

for $i= 1 to $x{

return $r}

}

print

Acknowledgement

http://spoken-tutorial.org/What is a Spoken Tutorial It summarises the Spoken Tutorial project If you do not have good bandwidth, you can download and watch it

Slide Number 12

Conducts workshops using spoken tutorials Gives certificates to those who pass an online test For more details, please write to contact@spoken-tutorial.org

It is supported by the National Mission on Education through ICT, MHRD, Government of India More information on this Mission is available at http://spoken-tutorial.org/NMEICT-Intro ]

This is Madhuri Ganpathi from IIT Bombay Thank you for joining