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Karel's Built in Commands

Commands

move();
Java
   
turnLeft();
Java
 
putBall();
Java
   
takeBall();
Java

Methods

Writing a Method

Writing a method is like teaching karel a new word.

Naming Methods: You can name your methods whatever you want, but you can't have spaces in the method name.

Remember that each open bracket { must match with a close bracket }

private void turnRight()
{
    turnLeft();
    turnLeft();
    turnLeft();
}

private void turnAround()
{
    turnLeft();
    turnLeft();
}

private void yourMethodName()
{
  // Code that will run when you make a call to
  // this method.
}
Java

Conditional Statements

If Statements

Remember that each open bracket { must match with a close bracket } 
if (condition)
{
  // code that will run if the condition is true
}
Java
if (condition)
{
  //code that will run if the condition is true
}
else
{
  //code that will run if condition is not true
}
Java

Example of if statements

if(frontIsClear())
{
  move();
}

if(ballsPresent())
{
  takeBall();
}
else
{
  move();
}
Java

Karel Conditions

Don't forget the () at the end 
frontIsClear()
leftIsClear()
rightIsClear()

facingNorth()
facingSouth()
facingEast()
facingWest()

ballsPresent()
Java
   
frontIsBlocked()
leftIsBlocked()
rightIsBlocked()

notFacingNorth()
notFacingSouth()
notFacingEast()
notFacingWest()

noBallsPresent()
Java

Loops

Remember that each open bracket { must match with a close bracket }

While Loops

while (CONDITION)
{
  // Code that will run while the CONDITION is true.
  // Once the CONDITION is no longer true,
  // it will stop.
}
Java

Example of while loops

/* This moves Karel to a wall */
while(frontIsClear())
{
    move();
}
Java

For Loops

for (int i=0; i < COUNT; i++)
{
  // Code that will run 'COUNT' times
}
Java

Example of for loops

/* This puts down 10 balls */
for(int i = 0; i < 10; i++)
{
    putBall();
}
Java
You can have multiple statements or function calls in a for loop. 
/* This puts down five balls and
   moves after each one */
for(int i = 0; i < 5; i++)
{
    putBall();
    move();
}
Java
Use for-loops when you want to repeat something a fixed number of times.
Use while-loops when you want to repeat something as long as a condition is true.

Comments

Comments

/* A multi-line comment describes your code
 * to someone who is reading it. */

// Use single line comments to clarify code.

/**
 *
 * A Javadoc comment
 * is used to describe how a
 * method or class works.
 *
 * It has two *'s on the first line.
 */
Java