66 lines
1.4 KiB
Markdown
66 lines
1.4 KiB
Markdown
# Forever
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Repeat code [in the background](/reference/control/in-background) forever.
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```sig
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basic.forever(() => {
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})
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```
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### Example: compass
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The following example constantly checks the [compass heading](/reference/input/compass-heading) and updates the screen with the direction.
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```blocks
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basic.forever(() => {
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let heading = input.compassHeading()
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if (heading < 45) {
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basic.showString("N", 100)
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} else if (heading < 135) {
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basic.showString("E", 100)
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}
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else if (heading < 225) {
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basic.showString("S", 100)
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}
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else {
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basic.showString("W", 100)
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}
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})
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```
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### Example: counter
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The following example continually shows the current value of a global variable:
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```blocks
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let num = 0
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basic.forever(() => {
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basic.showNumber(num, 150)
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})
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input.onButtonPressed(Button.A, () => {
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num = num + 1
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})
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```
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### Contention for the LED display
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If you have multiple processes that each show something on the LED screen, you may get unexpected results. Try, for example:
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```blocks
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basic.forever(() => {
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basic.showNumber(6789, 150)
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})
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input.onButtonPressed(Button.A, () => {
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basic.showNumber(2, 150)
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})
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```
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### Lessons
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[blink](/lessons/blink), [bounce-image](/lessons/bounce-image), [snowflake-fall](/lessons/snowflake-fall), [flashing-heart](/lessons/flashing-heart)
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### See also
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[while](/js/while), [on button pressed](/reference/input/on-button-pressed), [in background](/reference/control/in-background)
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