Need help, cant explain this part of code in Java

Question

for (char c : str.toCharArray()) {
        if (!Character.isDigit(c)) {
            return false;
        }
    }

Dont understand what mean condition of foor loop. How write this part of code in If/else form. Thank you.

Answer 1

The code means for each character in the string, if it's not a digit, return false. You can't write it purely in if/else form, as you need a loop to visit each character in the string.