LESSON 170 OF 404 · PROJECTS: EVERYDAY PROGRAMS

Password Strength V3 - Character Classes in Go

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:

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.
Use strconv.Itoa(n) to turn a number into text before joining it to a string.
The helper boolText(b) returns "True" or "False" for a boolean.

Try other passwords: with secret99 the output is

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

Use ASCII range comparisons: c >= 'A' && c <= 'Z' for uppercase, c >= 'a' && c <= 'z' for lowercase, c >= '0' && c <= '9' for digits, and the negation of all three for symbols.

password := "Secret!99"

length := len(password)
fmt.Println("Length: " + strconv.Itoa(length))
hasUpper := false
hasLower := false
hasDigit := false
hasSymbol := false
for _, char := range password {
	if char >= 'A' && char <= 'Z' {
		hasUpper = true
	}
	if char >= 'a' && char <= 'z' {
		hasLower = true
	}
	if char >= '0' && char <= '9' {
		hasDigit = true
	}
	if !((char >= 'A' && char <= 'Z') || (char >= 'a' && char <= 'z') || (char >= '0' && char <= '9')) {
		hasSymbol = true
	}
}
fmt.Println("Upper: " + boolText(hasUpper))
fmt.Println("Lower: " + boolText(hasLower))
fmt.Println("Digit: " + boolText(hasDigit))
fmt.Println("Symbol: " + boolText(hasSymbol))
if length >= 8 && hasUpper && hasLower && hasDigit && hasSymbol {
	fmt.Println("Strong")
} else {
	fmt.Println("Weak")
}

STEP 1 OF 13

Guided

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Password Strength V3 - Character Classes in Go

Password Strength V3 in Go