I'm trying to take a String input from Java Scanner and use it for a few different functions. Firstly, I want it able to use the input as text (not just numbers) for an unwritten method later on in the program. Secondly, I want to convert it to an int value (if the user for a different method (hasDupes) that has an int formal parameter.
I'm doing that currently like so:
public static boolean hasDupes(int num){
boolean[] digs = new boolean[10];
while (num > 0){
if (digs[num % 10])
return true;
digs[num % 10] = true;
num /= 10;
}
return false;
}
public static String getGuess() {
boolean validGuess = false;
String userGuess = "";
Scanner sc = new Scanner(System.in);
userGuess = sc.next();
if (!(hasDupes(Integer.parseInt(userGuess))) || (Integer.parseInt(userGuess) < 1000))
validGuess = true;
return userGuess;
}
However, when I input a value that isn't an int type, it gives me the error:
Exception in thread "main" java.lang.NumberFormatException: For input string: "nonIntText"
at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.base/java.lang.Integer.parseInt(Integer.java:652)
at java.base/java.lang.Integer.parseInt(Integer.java:770)
at Main.getGuess(Main.java:164)
What am I doing wrong?
When you try to convert a string into a number by Integer.parseInt or anything, it may throw NumberFormatException in case it is not a valid number.
public static String getGuess() {
Scanner scanner = new Scanner(System.in);
String text = scanner.next();
boolean isValid = false;
try {
// try to parse it to a number
double number = Double.parseDouble(text);
// now do something with number, call hasDupes()
isValid = true;
} catch (NumberFormatException ignored) {
// it is not a number
}
System.out.println("Is Valid '" + isValid + "'");
return text;
}
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