./curric/kotlin/basics/Characters/

Character

Characters are represented by the type Char. They can not be treated directly as numbers

fun check(c: Char) {
    if (c == 1) { // ERROR: incompatible types
        // ...
    }
}

Character literals go in single quotes: '1'. Special characters can be escaped using a backslash. The following escape sequences are supported: \t, \b, \n, \r, \', \", \\ and \$. To encode any other character, use the Unicode escape sequence syntax: '\uFF00'.

We can explicitly convert a character to an Int number:

fun decimalDigitValue(c: Char): Int {
    if (c !in '0'..'9') 
    // checks if the character is
    // between 0 and 9 on the ascii table
        throw IllegalArgumentException("Out of range")
    return c.toInt() - '0'.toInt() // Explicit conversions to numbers
}

ASCII is the numeric representation of characters that the computer sees

Like numbers, characters are boxed when a nullable reference is needed. Identity is not preserved by the boxing operation.