ios - How can I transform String from a TextField to Int in Swift 3? -

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• what “fatal error: unexpectedly found nil while unwrapping optional value” mean? 4 answers

i have function introduces new number using textfield:

//first node var root = treenode(7) @ibaction func introducirnumero(_ sender: any) {     var d = int(entrada1.text!)     print(d)     var call = treenode(d!)     root = treenode(d!)      //let numero: int? = (int(entrada1.text!)!)    } 

this function should cast type , send int class:

class treenode {     var value : int     var left  : treenode? = nil     var right : treenode? = nil      //incia como val     init(_ rootvalue:int)     { value = rootvalue }      @discardableresult  // if don't use method can send warning     func addvalue( _ newvalue:int) -> treenode     {         if newvalue == value // exclude duplicate entries         { return self }         else if newvalue < value         {             if let newnode = left?.addvalue(newvalue)             { return newnode }             left = treenode(newvalue)             return left!         }         else         {             if let newnode = right?.addvalue(newvalue)             { return newnode }             right = treenode(newvalue)             return right!         }      }   } 

the problem seems there no cast because receive error in line:

var d = int(entrada1.text!) 

and app crashes.

you can int("your number") , believe change int