Java Code Examples for java.util.Scanner#hasNextDouble()

public static double scanDouble() {
    Scanner in = new Scanner(System.in);
    boolean okay;
    do {
        System.out.print("Enter a number: ");
        if (in.hasNextDouble()) {
            okay = true;
        } else {
            okay = false;
            String word = in.next();
            System.err.println(word + " is not a number");
        }
    } while (!okay);
    double x = in.nextDouble();
    return x;
}
 

public AirMapPolygon(String polygonGeometry) {
    if (!polygonGeometry.toUpperCase().startsWith("POLYGON")) {
        throw new IllegalArgumentException("Illegal linestring");
    }
    List<Coordinate> coordinates = new ArrayList<>();
    int startIndex = polygonGeometry.indexOf('('); //This is where the coordinates will start
    int endIndex = polygonGeometry.indexOf(')');
    Scanner in = new Scanner(polygonGeometry.substring(startIndex, endIndex));
    while (in.hasNextDouble()) {
        double lat = in.nextDouble();
        if (in.hasNextDouble()) {
            double lng = in.nextDouble();
            coordinates.add(new Coordinate(lat, lng));
        }
    }
    in.close();
    setCoordinates(coordinates);
}
 

public AirMapPath(String lineString) {
    if (!lineString.toUpperCase().startsWith("LINESTRING")) {
        throw new IllegalArgumentException("Illegal linestring");
    }
    List<Coordinate> coordinates = new ArrayList<>();
    int startIndex = lineString.indexOf('('); //This is where the coordinates will start
    int endIndex = lineString.indexOf(')');
    Scanner in = new Scanner(lineString.substring(startIndex, endIndex));
    while (in.hasNextDouble()) {
        double lat = in.nextDouble();
        if (in.hasNextDouble()) {
            double lng = in.nextDouble();
            coordinates.add(new Coordinate(lat, lng));
        }
    }
    in.close();
    setCoordinates(coordinates);
}
 

private double valueOf (String text)
{
    Scanner scanner = new Scanner(text);
    scanner.useLocale(Locale.getDefault());

    while (scanner.hasNext()) {
        if (scanner.hasNextDouble()) {
            return scanner.nextDouble();
        } else {
            scanner.next();
        }
    }

    // Kludge!
    return Double.NaN;
}
 

private static double getUserDouble (String msg) {
    double input;
    while (true) {
        Scanner sc = new Scanner(System.in);
        System.out.print(msg);

        if (sc.hasNextDouble()) {
            input = sc.nextDouble();

            if (input <= 0) {
                System.out.println("Number must be positive.");
            } else {
                break;
            }

        } else {
            System.out.println("Invalid input.");
        }
    }
    return input;
}
 

public static List<Double> loadFromFile(String filepath) throws FileNotFoundException {
    File file = new File(filepath);
    Scanner scanner = new Scanner(file);
    List<Double> numbers = new ArrayList<>();
    while (scanner.hasNextDouble()) {
        double number = scanner.nextDouble();
        numbers.add(number);
    }
    scanner.close();
    return numbers;
}
 

public static void scanDouble2(Scanner in) {
    System.out.print("Enter a number: ");
    if (!in.hasNextDouble()) {
        String word = in.next();
        System.err.println(word + " is not a number");
        return;
    }
    double x = in.nextDouble();
    printLogarithm(x);
}
 

public static double scanDouble2() {
    Scanner in = new Scanner(System.in);
    while (true) {
        System.out.print("Enter a number: ");
        if (in.hasNextDouble()) {
            break;
        }
        String word = in.next();
        System.err.println(word + " is not a number");
    }
    double x = in.nextDouble();
    return x;
}
 

public AirMapPoint(String pointString) {
    int startIndex = pointString.indexOf('('); //This is where the coordinates will start
    int endIndex = pointString.indexOf(')');
    Scanner in = new Scanner(pointString.substring(startIndex, endIndex));
    if (in.hasNextDouble()) {
        double lat = in.nextDouble();
        if (in.hasNextDouble()) {
            double lng = in.nextDouble();
            setCoordinate(new Coordinate(lat, lng));
        }
    }
    in.close();
}
 

/**
     * Parses a string encoded KRL variable to a JOpenShowVar Variable
     *
     * @param callback the Callback from the robot
     * @return the JOpenShowVar Variable
     * @throws NumberFormatException on parsing error
     */
    public static Variable parseVariable(Callback callback) throws NumberFormatException {
        String variable = callback.getVariableName();
        String value = callback.getStringValue();
        int id = callback.getId();
        long readTime = callback.getReadTime();
//        int option = callback.getOption();

        Scanner sc = new Scanner(value);
        Variable var;
        if (sc.hasNextInt()) {
            var = new Int(id, variable, sc.nextInt(), readTime);
            sc.close();
        } else if (sc.hasNextFloat()) {
            var = new Real(id, variable, (double) sc.nextFloat(), readTime);
            sc.close();
        } else if (sc.hasNextDouble()) {
            var = new Real(id, variable, sc.nextDouble(), readTime);
            sc.close();
        } else if (sc.hasNextBoolean()) {
            var = new Bool(id, variable, sc.nextBoolean(), readTime);
            sc.close();
        }else if (value.contains("#")) {
            var = new Enum(id, variable, sc.nextLine(), readTime);
            sc.close();
        } else if (value.contains("{")) {
            sc.close();
            var = new Struct(id, variable, Struct.parseString(value), readTime);
        } else {
            var = new Real(id, variable, Double.parseDouble(value), readTime);
            sc.close();
        }
        return var;
    }
 

public static void main(String[] args) {
    int i = 0, t = 0;
    double a[] = new double[999999];
    Scanner x = new Scanner(System.in);
    a[i++] = Math.sqrt(x.nextDouble());
    t++;
    while (x.hasNextDouble()) {
        double d = x.nextDouble();
        a[i++] = Math.sqrt(d);
        t++;
    }
    for (int j = t - 1; j >= 0; j--) {
        System.out.printf("%.4f\n", a[j]);
    }
}
 

private static double getFirst(Scanner scanner) {
    if (scanner.hasNextDouble()) {
        return scanner.nextDouble();
    }

    return Double.NaN;
}
 

public static void scannerDemo2() {
	Scanner scan = new Scanner(System.in);

	double sum = 0;
	int m = 0;
	System.out.println("输入数字求平均，输入非数字结束！");
	while (scan.hasNextDouble()) {
		double x = scan.nextDouble();
		m = m + 1;
		sum = sum + x;
	}

	System.out.println(m + "个数的和为" + sum);
	System.out.println(m + "个数的平均值是" + (sum / m));
}
 

public Object interpret(Object val) throws IllegalArgumentException {
    String s = val.toString();
    Scanner sc = new Scanner(s);

    return sc.hasNextInt() ? sc.nextInt()
            : sc.hasNextLong() ? sc.nextLong()
            : sc.hasNextDouble() ? sc.nextDouble()
            : sc.hasNextBoolean() ? sc.nextBoolean()
            : sc.hasNextBigInteger() ? sc.nextBigInteger()
            : sc.hasNextFloat() ? sc.nextFloat()
            : sc.hasNextByte() ? sc.nextByte()
            : sc.hasNext() ? sc.next()
            : s;
}
 

/**
 *
 * @param val
 * @return
 * @throws IllegalArgumentException
 */
public Object interpret(Object val) throws IllegalArgumentException {
    String s = val.toString();
    Scanner sc = new Scanner(s);
    return sc.hasNextLong() ? sc.nextLong()
            : sc.hasNextInt() ? sc.nextInt()
            : sc.hasNextDouble() ? sc.nextDouble()
            : sc.hasNextBoolean() ? sc.nextBoolean()
            : sc.hasNextBigInteger() ? sc.nextBigInteger()
            : sc.hasNextFloat() ? sc.nextFloat()
            : sc.hasNextByte() ? sc.nextByte()
            : sc.hasNext() ? sc.next()
            : s;
}
 

/**
 * Parse a double with a default value.
 *
 * @param str string to parse
 * @param def default double value
 * @return parsed double
 */
public static Double parseDouble(String str, Double def) {
    if (str == null) {
        return def;
    }
    Scanner scnr = new Scanner(str);
    if (!scnr.hasNextDouble()) {
        return def;
    }
    return scnr.nextDouble();
}
 

/**
 * @param str string to check
 * @return whether the string is a double value
 */
public static boolean isDouble(String str) {
    if (str == null) {
        return false;
    }
    Scanner s = new Scanner(str.trim());
    if (!s.hasNextDouble()) {
        return false;
    }
    s.nextDouble();
    return !s.hasNext();
}
 

private static double sumAll(Scanner scanner) {

        double sum = 0.0d;
        while (scanner.hasNextDouble()) {
            sum += scanner.nextDouble();
        }

        return sum;
    }
 

/**
 * Converts the data from one schema to another. If the types are the same,
 * no change will be made, but simple conversions will be attempted for
 * other types.
 *
 * @param content
 *            The data to convert, generally taken from a field in an input
 *            Record.
 * @param inputSchema
 *            The schema of the content object
 * @param outputSchema
 *            The schema to convert to.
 * @return The content object, converted to the output schema.
 * @throws AvroConversionException
 *             When conversion is impossible, either because the output type
 *             is not supported or because numeric data failed to parse.
 */
private Object convertData(Object content, Schema inputSchema,
        Schema outputSchema) throws AvroConversionException {
    if (content == null) {
        // No conversion can happen here.
        if (supportsNull(outputSchema)) {
            return null;
        }
        throw new AvroConversionException("Output schema " + outputSchema
                + " does not support null");
    }

    Schema nonNillInput = getNonNullSchema(inputSchema);
    Schema nonNillOutput = getNonNullSchema(outputSchema);
    if (nonNillInput.getType().equals(nonNillOutput.getType())) {
        return content;
    } else {
        if (nonNillOutput.getType() == Schema.Type.STRING) {
            return content.toString();
        }

        // For the non-string cases of these, we will try to convert through
        // string using Scanner to validate types. This means we could
        // return questionable results when a String starts with a number
        // but then contains other content
        Scanner scanner = new Scanner(content.toString());
        scanner.useLocale(locale);
        switch (nonNillOutput.getType()) {
        case LONG:
            if (scanner.hasNextLong()) {
                return scanner.nextLong();
            } else {
                throw new AvroConversionException("Cannot convert "
                        + content + " to long");
            }
        case INT:
            if (scanner.hasNextInt()) {
                return scanner.nextInt();
            } else {
                throw new AvroConversionException("Cannot convert "
                        + content + " to int");
            }
        case DOUBLE:
            if (scanner.hasNextDouble()) {
                return scanner.nextDouble();
            } else {
                throw new AvroConversionException("Cannot convert "
                        + content + " to double");
            }
        case FLOAT:
            if (scanner.hasNextFloat()) {
                return scanner.nextFloat();
            } else {
                throw new AvroConversionException("Cannot convert "
                        + content + " to float");
            }
        default:
            throw new AvroConversionException("Cannot convert to type "
                    + nonNillOutput.getType());
        }
    }
}
 

/**
 * Converts the data from one schema to another. If the types are the same,
 * no change will be made, but simple conversions will be attempted for
 * other types.
 *
 * @param content
 *            The data to convert, generally taken from a field in an input
 *            Record.
 * @param inputSchema
 *            The schema of the content object
 * @param outputSchema
 *            The schema to convert to.
 * @return The content object, converted to the output schema.
 * @throws AvroConversionException
 *             When conversion is impossible, either because the output type
 *             is not supported or because numeric data failed to parse.
 */
private Object convertData(Object content, Schema inputSchema,
        Schema outputSchema) throws AvroConversionException {
    if (content == null) {
        // No conversion can happen here.
        if (supportsNull(outputSchema)) {
            return null;
        }
        throw new AvroConversionException("Output schema " + outputSchema
                + " does not support null");
    }

    Schema nonNillInput = getNonNullSchema(inputSchema);
    Schema nonNillOutput = getNonNullSchema(outputSchema);
    if (nonNillInput.getType().equals(nonNillOutput.getType())) {
        return content;
    } else {
        if (nonNillOutput.getType() == Schema.Type.STRING) {
            return content.toString();
        }

        // For the non-string cases of these, we will try to convert through
        // string using Scanner to validate types. This means we could
        // return questionable results when a String starts with a number
        // but then contains other content
        Scanner scanner = new Scanner(content.toString());
        scanner.useLocale(locale);
        switch (nonNillOutput.getType()) {
        case LONG:
            if (scanner.hasNextLong()) {
                return scanner.nextLong();
            } else {
                throw new AvroConversionException("Cannot convert "
                        + content + " to long");
            }
        case INT:
            if (scanner.hasNextInt()) {
                return scanner.nextInt();
            } else {
                throw new AvroConversionException("Cannot convert "
                        + content + " to int");
            }
        case DOUBLE:
            if (scanner.hasNextDouble()) {
                return scanner.nextDouble();
            } else {
                throw new AvroConversionException("Cannot convert "
                        + content + " to double");
            }
        case FLOAT:
            if (scanner.hasNextFloat()) {
                return scanner.nextFloat();
            } else {
                throw new AvroConversionException("Cannot convert "
                        + content + " to float");
            }
        default:
            throw new AvroConversionException("Cannot convert to type "
                    + nonNillOutput.getType());
        }
    }
}