unärer Operator ‚-‘ kann nicht auf einen Operanden vom Typ angewandt werden ‚@lvalue Int‘

Question

@IBAction func blueBtnAct(_ sender: AnyObject) { 
    score++ //error bcause Unary operator '++' cannot be applied to an operand of type '@lvalue Int' 
    blueLbl.text = "\(score)" 
    GrenLbl.text = "\(score)" 
    testScore() 
} 
@IBAction func GrenBtnAct(_ sender: AnyObject) { 
    score-- //error bcause Unary operator '--' cannot be applied to an operand of type '@lvalue Int' 
    blueLbl.text = "\(score)" 
    GrenLbl.text = "\(score)" 
    testScore() 
} 

Answer 1

Sie sollten score = score + 1 Verwendung anstelle von score++