//
// This program demonstrates how to extract the first digit
// of a floating‑point number in a clear and expressive way.
//
// Approach:
// - Convert the float to a string using String().
// - If the number is negative, skip the leading '-' sign.
// - Read the first numeric character.
// - Convert that character back into an integer.
//
/// Returns the first digit of a floating‑point number.
/// Works for both positive and negative values.
func firstDigit(of value: Double) -> Int {
let text: String = String(value)
// Skip the leading '-' for negative numbers
let firstChar: Character =
text.hasPrefix("-")
? text[text.index(text.startIndex, offsetBy: 1)]
: text[text.startIndex]
// Convert the character to an integer
return Int(String(firstChar))!
}
/// Main execution block.
func main() {
let f: Double = 376.287152
let digit: Int = firstDigit(of: f)
print(digit)
}
// Run the program
main()
/*
run:
3
*/
