67 lines
2.0 KiB
Markdown
67 lines
2.0 KiB
Markdown
# Function Parameters
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How to use parameters to pass info in and out of an function.
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### @parent js/function
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A [function](/microbit/js/function) can have multiple input parameters and/or a single output parameter. The parameters must be one of the supported variable [types](/microbit/js/types).
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When you first [create a function](/microbit/js/function), it looks like this:
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```
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export function doStuff() {
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}
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```
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### Add a function parameter
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1. Open your script (if needed) and then click `script` in the upper-right corner.
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2. Under **code** click your function name.
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3. Click the function name in your code (this opens the function panel).
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4. Click **add input parameter** or **add output parameter**. The parameter is added to your function.
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#### Input parameters
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The default type for an input parameter is [Number](/microbit/reference/types/number):
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```
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export function oneInput(p: number) {
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}
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```
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To change the default type, click the type ([Number](/microbit/reference/types/number) in this case) and change it to [String](/microbit/reference/types/string), [Boolean](/microbit/reference/types/boolean), or [Image](/microbit/reference/image/image). You can add multiple input parameters to a function.
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#### Output parameter
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the default type for an output parameter is [Number](/microbit/reference/types/number):
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```
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export function output() : number {
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let r: number
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return 42
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return r
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}
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```
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To change the default type, click the type ([Number](/microbit/reference/types/number) in this case) and change it to [String](/microbit/reference/types/string), [Boolean](/microbit/reference/types/boolean), or [Image](/microbit/reference/image/image).
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### Inputs and output function
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The following sample function has two inputs and one output parameter (all are the Number type):
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```
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export function inputsAndOutput(p: number, q: number) : number {
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let r: number
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return p + q
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return r
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}
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```
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### See also
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[call a function](/microbit/js/call), [create a function](/microbit/js/function), [return](/microbit/js/return)
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