C Block

The general shape of a C block

A C block is a block that is shaped like the letter "C" so other blocks can fit inside it. These blocks perform the conditions and loops.

Shape

C blocks have a "mouth" (it looks like the letter "C", hence the name) — the blocks that will be placed inside the C block go in these mouths. All but one of the C blocks consist of one mouth — the other, if <> then, else, consists of two mouths. (For this reason, this block is occasionally referred to as an "E block".) When any of the other C blocks are dragged over a stack of blocks — if the C is empty — its mouth extends to wrap around them.

repeat (10)
repeat until <(loudness) > [30]>
glide (1) secs to x: (10) y: (0)
wait (1) secs
go to x: (0) y: (0)
end
play sound (meow v) until done
end

In Scratch 1.2 and earlier, C-block scripts could only be built one block at a time.

Most C blocks, like Stack Blocks, have a notch on the top of the block and a bump on the bottom, signifying that other blocks can be stacked above or below them. The forever block is an exception in that it only has a notch, as if blocks could be placed under it, they would never run.

C Blocks in Scratch 3.0

In Scratch 3.0, there are five C blocks, and they can all be found in the Control category.

Note:

Click on a block for more information.

• repeat ()
• forever — this block is also a Cap Block.
• if <> then

• if <> then
  else

• repeat until <>

Removed C Blocks

This article or section documents something not included in the current version of Scratch (3.0). It is only useful from a historical perspective.

forever if <> {
} :: control cap

The Forever If () block.

In Scratch 1.4 and earlier, the forever if <>::control block could be used. This can be recreated with this workaround:

forever
if <> then
end
end

Uses

As C blocks are for checks and loops, they are used in many places. Some uses include:

• Creating a scripts which runs forever

when gf clicked
forever
turn cw (15) degrees

• Checking a condition

when [space v] key pressed
if <(loudness) > [30]> then
stop [all v]
end

• Repeating an animation a certain amount of times

when gf clicked
repeat (200)
turn ccw (36) degrees
change [color v] effect by (1)
end

Here is an example for both checks and looping:

when I receive [Decrease health v]
change [Health v] by (-1)
if <(health) = [0]> then
repeat (8)
change [color v] effect by (25)
end
end

There is a check (the If () Then block is checking if the variable Health has a value of 0), and inside the check is a repeat loop (with the Repeat () block). Note how C blocks can be placed inside other C blocks.