LESSON 170 OF 414 · PROJECTS: EVERYDAY PROGRAMS

Password Strength V3 - Character Classes in Kotlin

Practice

Track four boolean flags for a password: does it contain an uppercase letter, a lowercase letter, a digit, and a symbol (non-alphanumeric)?

You start with:

val password = "Secret!99"

Build:

Length: 9
Upper: True
Lower: True
Digit: True
Symbol: True
Strong

Rules:

Print "Length: " followed by the number of characters.
Start four flags (hasUpper, hasLower, hasDigit, hasSymbol) at false. Loop over every character and set the matching flag to true.
A symbol is any character that is not a letter and not a digit.
Print one line per flag, in this order: "Upper: ", "Lower: ", "Digit: ", "Symbol: ", each followed by the flag. Write it as True or False with a capital letter, exactly as in the example (your language's own boolean prints differently, so choose the text yourself).
If the length is at least 8 and all four flags are true (stricter than the last lesson), print Strong; otherwise print Weak.

Try other passwords: with secret99 the output is

Length: 8
Upper: False
Lower: True
Digit: True
Symbol: False
Weak

Use c.isUpperCase(), c.isLowerCase(), c.isDigit() and c.isLetterOrDigit() inside for (c in password).

val password = "Secret!99"

val length = password.length
println("Length: $length")
var hasUpper = false
var hasLower = false
var hasDigit = false
var hasSymbol = false
for (c in password) {
    if (c.isUpperCase()) {
        hasUpper = true
    }
    if (c.isLowerCase()) {
        hasLower = true
    }
    if (c.isDigit()) {
        hasDigit = true
    }
    if (!c.isLetterOrDigit()) {
        hasSymbol = true
    }
}
println("Upper: " + (if (hasUpper) "True" else "False"))
println("Lower: " + (if (hasLower) "True" else "False"))
println("Digit: " + (if (hasDigit) "True" else "False"))
println("Symbol: " + (if (hasSymbol) "True" else "False"))
if (length >= 8 && hasUpper && hasLower && hasDigit && hasSymbol) {
    println("Strong")
} else {
    println("Weak")
}

STEP 1 OF 13

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Password Strength V3 - Character Classes in Kotlin

Password Strength V3 in Kotlin