edu.harvard

Class CS50

java.lang.Object

edu.harvard.CS50

public class CS50
extends Object

Method Summary

Methods

Modifier and Type	Method and Description
static void	eprintf(String format, Object... args) Prints an error message, formatted like PrintStream.printf(java.lang.String, java.lang.Object...), to standard error, prefixing it with program's name as well as the file and line number from which method was called.
static char	getChar(String prompt) Reads a line of text from standard input and returns the equivalent char; if text does not represent a char, user is prompted to retry.
static double	getDouble(String prompt) Reads a line of text from standard input and returns the equivalent double as precisely as possible; if text does not represent a double or if value would cause underflow or overflow, user is prompted to retry.
static float	getFloat(String prompt) Reads a line of text from standard input and returns the equivalent float as precisely as possible; if text does not represent a float or if value would cause underflow or overflow, user is prompted to retry.
static int	getInt(String prompt) Reads a line of text from standard input and returns it as an int in [-231, 231 - 1) if possible; if text does not represent such an int or if value would cause underflow or overflow, user is prompted to retry.
static long	getLong(String prompt) Reads a line of text from standard input and returns an equivalent long in [-263, 263 - 1) if possible; if text does not represent such a long or if value would cause underflow or overflow, user is prompted to retry.
static String	getString(String prompt) Reads a line of text from standard input and returns it as a String, sans trailing line ending.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

eprintf

public static void eprintf(String format,
           Object... args)

Prints an error message, formatted like PrintStream.printf(java.lang.String, java.lang.Object...), to standard error, prefixing it with program's name as well as the file and line number from which method was called.

Parameters:

format - A format string as described in Format string syntax

args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion.

getChar

public static char getChar(String prompt)

Reads a line of text from standard input and returns the equivalent char; if text does not represent a char, user is prompted to retry. If line can't be read, returns Character.MAX_VALUE.

Parameters:

prompt - A string that prompts the user to provide input.

Returns:

char

getDouble

public static double getDouble(String prompt)

Reads a line of text from standard input and returns the equivalent double as precisely as possible; if text does not represent a double or if value would cause underflow or overflow, user is prompted to retry. If line can't be read, returns Double.MAX_VALUE.

Parameters:

prompt - A string that prompts the user to provide input.

Returns:

double

getFloat

public static float getFloat(String prompt)

Reads a line of text from standard input and returns the equivalent float as precisely as possible; if text does not represent a float or if value would cause underflow or overflow, user is prompted to retry. If line can't be read, returns Float.MAX_VALUE.

Parameters:

prompt - A string that prompts the user to provide input.

Returns:

float

getInt

public static int getInt(String prompt)

Reads a line of text from standard input and returns it as an int in [-2³¹, 2³¹ - 1) if possible; if text does not represent such an int or if value would cause underflow or overflow, user is prompted to retry. If line can't be read, returns Integer.MAX_VALUE.

Parameters:

prompt - A string that prompts the user to provide input.

Returns:

int

getLong

public static long getLong(String prompt)

Reads a line of text from standard input and returns an equivalent long in [-2⁶³, 2⁶³ - 1) if possible; if text does not represent such a long or if value would cause underflow or overflow, user is prompted to retry. If line can't be read, returns Long.MAX_VALUE.

Parameters:

prompt - A string that prompts the user to provide input.

Returns:

long

getString

public static String getString(String prompt)

Reads a line of text from standard input and returns it as a String, sans trailing line ending. Supports CR (\r), LF (\n), and CRLF (\r\n) as line endings. Returns "" if user inputs only CR, LF, or CRLF. Returns "" upon no input whatsoever (i.e., EOF). Returns null upon error.

Parameters:

prompt - A string that prompts the user to provide input.

Returns:

String