153 lines
3.0 KiB
Markdown
153 lines
3.0 KiB
Markdown
---
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id: boolean-if-else
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title: Boolean, If, Else
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---
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## Boolean
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The type of a Boolean is `bool` and the possible values are `True` and `False`.
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Here's how to define a boolean:
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<!--DOCUSAURUS_CODE_TABS-->
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<!--Pascaligo-->
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```pascaligo
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const a: bool = True;
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const b: bool = False;
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```
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<!--Cameligo-->
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```cameligo
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let a: bool = true
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let b: bool = false
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```
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<!--END_DOCUSAURUS_CODE_TABS-->
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## Comparing two values
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In LIGO, only values of the same type can be compared. We call these "comparable types." Comparable types include e.g. `int`, `nat`, `string`, `tez`, `timestamp`, `address`, ...
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### Comparing strings
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<!--DOCUSAURUS_CODE_TABS-->
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<!--Pascaligo-->
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```pascaligo
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const a: string = "Alice";
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const b: string = "Alice";
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// True
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const c: bool = (a = b);
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```
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<!--Cameligo-->
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```cameligo
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let a: string = "Alice"
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let b: string = "Alice"
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// true
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let c: bool = (a = b)
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```
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<!--END_DOCUSAURUS_CODE_TABS-->
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### Comparing numbers
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<!--DOCUSAURUS_CODE_TABS-->
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<!--Pascaligo-->
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```pascaligo
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const a: int = 5;
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const b: int = 4;
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const c: bool = (a = b);
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const d: bool = (a > b);
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const e: bool = (a < b);
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const f: bool = (a <= b);
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const g: bool = (a >= b);
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const h: bool = (a =/= b);
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```
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<!--Cameligo-->
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```cameligo
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let a: int = 5
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let b: int = 4
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let c: bool = (a = b)
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let d: bool = (a > b)
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let e: bool = (a < b)
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let f: bool = (a <= b)
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let g: bool = (a >= b)
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let h: bool = (a =/= b)
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```
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<!--END_DOCUSAURUS_CODE_TABS-->
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### Comparing tez
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> 💡 Comparing `tez` values is especially useful when dealing with an `amount` sent in a transaction.
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<!--DOCUSAURUS_CODE_TABS-->
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<!--Pascaligo-->
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```pascaligo
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const a: tez = 5mutez;
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const b: tez = 10mutez;
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const c: bool = (a = b);
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```
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<!--Cameligo-->
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```cameligo
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let a: tez = 5mutez
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let b: tez = 10mutez
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// false
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let c: bool = (a = b)
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```
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<!--END_DOCUSAURUS_CODE_TABS-->
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## Conditionals, if staments, and more
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Conditional logic is an important part of every real world program.
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### If/else statements
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<!--DOCUSAURUS_CODE_TABS-->
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<!--Pascaligo-->
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```pascaligo
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const min_age: nat = 16n;
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(*
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This function is really obnoxious, but it showcases
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how the if statement and it's syntax can be used.
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Normally, you'd use `with (age > min_age)` instead.
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*)
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function is_adult(const age: nat): bool is
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block {
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var is_adult: bool := False;
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if (age > min_age) then begin
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is_adult := True;
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end else begin
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is_adult := False;
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end
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} with is_adult
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```
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> You can run the function above with
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> ```
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> ligo run-function -s pascaligo src/if-else.ligo is_adult 21n
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> ```
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<!--Cameligo-->
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```cameligo
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let min_age: nat = 16n
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(**
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This function is really obnoxious, but it showcases
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how the if statement and it's syntax can be used.
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Normally, you'd use `with (age > min_age)` instead.
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*)
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let is_adult (age: nat) : bool =
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if (age > min_age) then true else false
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```
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> You can run the function above with
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> ```
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> ligo run-function -s cameligo src/if-else.mligo is_adult 21n
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> ```
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<!--END_DOCUSAURUS_CODE_TABS--> |