var myBool: Bool = true
if myBool == true {	// myBool is true here
}
else {	// myBool is false here
}

// check whether a number is positive, negative, or 0.
let number = 0
if (number > 0) { print("Number is positive.")
}
else if (number < 0) { print("Number is negative")
}
else { print("Number is 0.")
}
print("This statement is always executed")

let number = 10
// check if number is greater than 0
if (number > 0) { print("Number is positive.")
}
print("The if statement is easy")

var someValue:Int?
var someAnotherValue:Int! = 0
if someValue != nil {	print("It has some value \(someValue!)")
} else {	print("doesn't contain value")
}
if someAnotherValue != nil {	print("It has some value \(someAnotherValue!)")
} else {	print("doesn't contain value")
}

if (condition) { // body of if statement
}