Java prevents users from entering anything other than integers
My intentions are to take string input from the user and only accept integer values. Perhaps what I have is not the best approach to this, and if this case tells me how I should change my program. Let's say the user enters values such as 1 2 3 4 a 5
. How can I prevent this little error.
String[] intVal;
String inputValues;
int[] numbers = new int[20];
int count = 0;
InputStreamReader reader = new InputStreamReader(System.in);
BufferedReader input = new BufferedReader(reader);
System.out.print("Enter up to 20 integer values here: ");
inputValues = input.readLine();
intVal = inputValues.split("\\s");
for(int i = 0; i < intVal.length; i++){
numbers[i] = Integer.parseInt(intVal[i]);
count++;
}
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Integer.parseInt(String s)
emits a NumberFormatException
if the input was not a number (see the Javadoc on Integer.parseInt(String s)
).
You can do something like
for (int i = 0; i < intVal.length; i++) {
try {
numbers[i] = Integer.parseInt(intVal[i]);
count++;
}
catch (NumberFormatException ex) {
System.out.println(i + " is not a number. Ignoring this value..."); // Or do something else
}
}
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Many possible solutions, one of which throws an exception that parseInt
throws and asks the user to enter a different sequence.
But I would use nextInt
and hasNextInt
and ignore any character that is not a number.
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