Java Reference
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+ "Input not an integer");
return (int) tokenizer.nval;
Directory "TestFormattedInput"
The Integer class makes the maximum and minimum values of type int available in the public mem-
bers MAX_VALUE and MIN_VALUE . Other classes corresponding to the basic numeric types provide similar
fields. To determine whether the value in nval is really a whole number, you cast it to an integer and then
cast it back to double and see whether it is the same value.
The code to implement readDouble() is very simple. You don't need the cast for the value in nval be-
cause it is type double anyway:
public double readDouble() throws InvalidUserInputException {
if (readToken() != StreamTokenizer.TT_NUMBER) {
throw new InvalidUserInputException("readDouble() failed."
+ "Input data not numeric");
return tokenizer.nval;
Directory "TestFormattedInput"
A readFloat() method would just need to cast nval to type float .
Reading a string is slightly more involved. You could allow input strings to be quoted or unquoted as
long as they were alphanumeric and did not contain whitespace characters. Here's how the method might
be coded to allow that:
public String readString() throws InvalidUserInputException {
if (readToken() == StreamTokenizer.TT_WORD || ttype == '\"'
|| ttype == '\"') {
return tokenizer.sval;
} else {
throw new InvalidUserInputException("readString() failed."
+ "Input data is not a
Directory "TestFormattedInput"
If either a word or a string is recognized, the token is stored as type String in the sval field of the
StreamTokenizer object.
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