Control

Introduction

The Control blocks in VEXcode V5 manage the flow of a project by handling loops, conditions, delays, and stopping execution.

Below is a list of available blocks:

• wait – Pauses execution for a specific duration.

• wait until – Pauses execution until a specified condition is met.

• repeat – Repeats enclosed blocks a specific number of times.

• forever – Repeats enclosed blocks indefinitely.

• repeat until – Repeats enclosed blocks until a condition is met.

• while – Repeats enclosed blocks while a condition remains true.

• if – Runs enclosed blocks if a condition is true.

• if / else – Runs one set of blocks if a condition is true, otherwise runs another.

• if / else if / else – Runs different sets of blocks depending on multiple conditions.

• break – Exits a repeat, forever, repeat until, or while loop immediately.

• stop project – Ends the execution of the project.

wait

The wait block pauses for a specific amount of time before moving to the next block.

wait stack block

    wait (1) seconds

Parameters	Description
time	The amount of time to wait, as a positive integer or decimal in seconds.

Example

When started, moves forward for one second, then stops all movement.

    when started
    [Move forward for one second, then stop.]
    drive [forward v]
    wait (1) seconds
    stop driving

wait Until

The wait until block pauses execution until a specified condition is met before proceeding to the next block.

wait until stack block

    wait until <>

Parameters	Description
condition	The condition that must be met before moving on to the next block.

Example

When started, moves forward until the screen is pressed, then stops all movement.

    when started
    [Move forward until the screen is pressed, then stop.]
    drive [forward v]
    wait until <screen pressed?>
    stop driving

repeat

The repeat block runs the blocks inside it a set number of times.

repeat c block

    repeat [10]
    end

Parameters	Description
times	A whole number that sets how many times the repeat block runs.

Example

    when started
    [Move in a square path.]
    repeat [4]
        drive [forward v] for [150] [mm v] ▶
        turn [right v] for [90] degrees ▶
    end

forever

The forever block keeps running the blocks inside it again and again without stopping.

forever c block

    forever
    end

Parameters	Description
	This block has no parameters.

Example

When started, continuously moves in a square path by moving forward 50 mm and turning right 90 degrees in an infinite loop.

    when started
    [Move in a square path forever.]
    forever
        drive [forward v] for [150] [mm v] ▶
        turn [right v] for [90] degrees ▶
    end

repeat until

The repeat until block executes the enclosed blocks repeatedly while the condition evaluates as False.

repeat until block

    repeat until <>
    end

Parameters	Description
condition	An expression or variable that is evaluated before each iteration. If it evaluates as: False - The loop continues True - The loop stops

Example

When started, keeps all LEDs red until the screen is pressed, then turns them off.

    when started
    [Turn until the screen is pressed.]
    repeat until <screen pressed?>
        turn [right v]
    end
    stop driving

while

The while block executes the enclosed blocks repeatedly while the condition evaluates as True.

while c block

    while <>
    end

Parameters	Description
condition	An expression or variable that is evaluated before each iteration. If it evaluates as: True - The loop continues False - The loop stops

Example

A stack of blocks that begins with a when started block, followed by a comment block reading Display the time after 2 seconds have passed. A wait until block pauses execution until the timer reaches or exceeds two seconds. Once this condition is met, a print block displays the timer value on the screen.

  when started
  [Display the time for one minute.]
  while <(timer in seconds) [math_less_than v] [60] >
  clear screen
  set cursor to row [1] column [1] on screen
  print (timer in seconds) on screen ▶

if

The if block executes the enclosed block of code if the condition evaluates as True.

if block

    if <> then
    end

Parameters	Description
condition	An expression or variable that is evaluated when the statement runs. If it evaluates as: True - The code inside the if block executes False - The block is skipped

Example

When started, continuously checks if the screen is pressed. If pressed, the robot kicks an object with medium force.

    when started
    [Turn in a circle if the screen is pressed.]
    forever
    if <screen pressed?> then
    turn [right v] for [360] degrees ▶
    end
    stop driving
    end

if / else

The if / else block determines which enclosed block of code runs based on whether the condition evaluates as True or False.

if then else block

    if <> then
    else
    end

Parameters	Description
condition	An expression or variable that is evaluated when the statement runs. If it evaluates as: True - The code inside the if block executes False - The code inside the else block executes instead

Example

if then else block

    when started
    [Display a message if the screen is being pressed.]
    forever
    clear screen
    set cursor to row [1] column [1] on screen
    if <screen pressed?> then
        print [Pressed!] on screen ▶
    else
        print [Not pressed!] on screen ▶
    end

if / else if / else

The if / else if / else block structure selects which enclosed block of code runs based on conditions:

• if runs its block of code if the condition evaluates as True.

• else if checks additional conditions only if all previous conditions evaluated as False. Multiple else if statements can be used.

• else runs its block of code only if none of the previous conditions evaluated as True.

if else if else block

    if <> then
    else if <> then
    else 
    end

Parameters	Description
condition	An expression or variable that is evaluated when the statement runs. The first condition that evaluates as: True - Determines which block of code executes False - If none are True, the else block of code runs

Example

if then else block

    when started
    [Move the robot based on the Controller button is being pressed.]
    forever
    if <[Controller1 v] [▶ v] pressed?> then
        turn [right v]
    else if <[Controller1 v] [◀ v] pressed?> then
        turn [left v]
    else
        stop driving
    end

break

The break block exits a loop immediately.

break stack block

    break

Parameters	Description
	This block has no parameters.

Example

When started, turns right until the screen is pressed, then stops.

    when started
    [Stop turning after the screen is pressed.]
    forever
    turn [right v]
    if <screen pressed?> then
    break
    end
    end
    stop driving

stop project

The stop project block ends a running project.

stop project block

    stop project

Parameters	Description
	This block has no parameters.

Example

When started, turns right until the screen is pressed, then stops the project.

    when started
    [Stop the project entirely after the screen is pressed.]
    forever
    turn [right v]
    if <screen pressed?> then
    stop project
    end
    end