--- id: boolean-if-else title: Boolean, If, Else --- ## Boolean The type of a Boolean is `bool` and the possible values are `True` and `False`. Here's how to define a boolean: ```pascaligo group=a const a: bool = True; const b: bool = False; ``` ```cameligo group=a let a: bool = true let b: bool = false ``` ```reasonligo group=a let a: bool = true; let b: bool = false; ``` ## Comparing two values 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`, ... ### Comparing strings ```pascaligo group=b const a: string = "Alice"; const b: string = "Alice"; // True const c: bool = (a = b); ``` ```cameligo group=b let a: string = "Alice" let b: string = "Alice" // true let c: bool = (a = b) ``` ```reasonligo group=b let a: string = "Alice"; let b: string = "Alice"; (* true *) let c: bool = (a == b); ``` ### Comparing numbers ```pascaligo group=c const a: int = 5; const b: int = 4; const c: bool = (a = b); const d: bool = (a > b); const e: bool = (a < b); const f: bool = (a <= b); const g: bool = (a >= b); const h: bool = (a =/= b); ``` ```cameligo group=c let a: int = 5 let b: int = 4 let c: bool = (a = b) let d: bool = (a > b) let e: bool = (a < b) let f: bool = (a <= b) let g: bool = (a >= b) let h: bool = (a <> b) ``` ```reasonligo group=c let a: int = 5; let b: int = 4; let c: bool = (a == b); let d: bool = (a > b); let e: bool = (a < b); let f: bool = (a <= b); let g: bool = (a >= b); let h: bool = (a != b); ``` ### Comparing tez > 💡 Comparing `tez` values is especially useful when dealing with an `amount` sent in a transaction. ```pascaligo group=d const a: tez = 5mutez; const b: tez = 10mutez; const c: bool = (a = b); ``` ```cameligo group=d let a: tez = 5mutez let b: tez = 10mutez // false let c: bool = (a = b) ``` ```reasonligo group=d let a: tez = 5mutez; let b: tez = 10mutez; (* false *) let c: bool = (a == b); ``` ## Conditionals, if staments, and more Conditional logic is an important part of every real world program. ### If/else statements ```pascaligo group=e const min_age: nat = 16n; function is_adult(const age: nat): bool is if (age > min_age) then True else False ``` > You can run the function above with > ``` > ligo run-function -s pascaligo src/if-else.ligo is_adult 21n > ``` ```cameligo group=e let min_age: nat = 16n (** This function is really obnoxious, but it showcases how the if statement and its syntax can be used. Normally, you'd use `with (age > min_age)` instead. *) let is_adult (age: nat) : bool = if (age > min_age) then true else false ``` ```reasonligo group=e let min_age: nat = 16n; (** This function is really obnoxious, but it showcases how the if statement and its syntax can be used. Normally, you'd use `with (age > min_age)` instead. *) let is_adult = (age: nat): bool => if (age > min_age) { true; } else { false; }; ``` > You can run the function above with > ``` > ligo run-function -s reasonligo src/if-else.religo is_adult 21n > ```