In (Introduction to Programming in Java

java.lang.Object
- edu.princeton.cs.introcs.In

```
public final class In
extends Object
```
Input. This class provides methods for reading strings and numbers from standard input, file input, URLs, and sockets.
The Locale used is: language = English, country = US. This is consistent with the formatting conventions with Java floating-point literals, command-line arguments (via Double.parseDouble(String)) and standard output.
For additional documentation, see Section 3.1 of Introduction to Programming in Java: An Interdisciplinary Approach by Robert Sedgewick and Kevin Wayne.
Like Scanner, reading a token also consumes preceding Java whitespace, reading a full line consumes the following end-of-line delimeter, while reading a character consumes nothing extra.
Whitespace is defined in Character.isWhitespace(char). Newlines consist of \n, \r, \r\n, and Unicode hex code points 0x2028, 0x2029, 0x0085; see Scanner.java (NB: Java 6u23 and earlier uses only \r, \r, \r\n).

Author:

David Pritchard, Robert Sedgewick, Kevin Wayne

Constructor Summary

Constructors
Constructor and Description
`In()` Create an input stream from standard input.
`In(File file)` Create an input stream from a file.
`In(Scanner scanner)` Create an input stream from a given Scanner source; use with `new Scanner(String)` to read from a string.
`In(Socket socket)` Create an input stream from a socket.
`In(String s)` Create an input stream from a filename or web page name.
`In(URL url)` Create an input stream from a URL.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`close()` Close the input stream.
`boolean`	`exists()` Does the input stream exist?
`boolean`	`hasNextChar()` Is the input empty (including whitespace)? Use this to know whether the next call to `readChar()` will succeed.
`boolean`	`hasNextLine()` Does the input have a next line? Use this to know whether the next call to `readLine()` will succeed.
`boolean`	`isEmpty()` Is the input empty (except possibly for whitespace)? Use this to know whether the next call to `readString()`, `readDouble()`, etc will succeed.
`static void`	`main(String[] args)` Test client.
`String`	`readAll()` Read and return the remainder of the input as a string.
`double[]`	`readAllDoubles()` Read all doubles until the end of input is reached, and return them.
`int[]`	`readAllInts()` Read all ints until the end of input is reached, and return them.
`String[]`	`readAllStrings()` Read all strings until the end of input is reached, and return them.
`boolean`	`readBoolean()` Read and return the next boolean, allowing case-insensitive "true" or "1" for true, and "false" or "0" for false.
`byte`	`readByte()` Read and return the next byte.
`char`	`readChar()` Read and return the next character.
`double`	`readDouble()` Read and return the next double.
`static double[]`	`readDoubles()` Deprecated. Clearer to use `StdIn.readAllDoubles()`
`static double[]`	`readDoubles(String filename)` Deprecated. Clearer to use `new In(filename)`.`readAllDoubles()`
`float`	`readFloat()` Read and return the next float.
`int`	`readInt()` Read and return the next int.
`static int[]`	`readInts()` Deprecated. Clearer to use `StdIn.readAllInts()`
`static int[]`	`readInts(String filename)` Deprecated. Clearer to use `new In(filename)`.`readAllInts()`
`String`	`readLine()` Read and return the next line.
`long`	`readLong()` Read and return the next long.
`short`	`readShort()` Read and return the next short.
`String`	`readString()` Read and return the next string.
`static String[]`	`readStrings()` Deprecated. Clearer to use `StdIn.readAllStrings()`
`static String[]`	`readStrings(String filename)` Deprecated. Clearer to use `new In(filename)`.`readAllStrings()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - In
```
public In()
```
    Create an input stream from standard input.
  - In
```
public In(Socket socket)
```
    Create an input stream from a socket.
  - In
```
public In(URL url)
```
    Create an input stream from a URL.
  - In
```
public In(File file)
```
    Create an input stream from a file.
  - In
```
public In(String s)
```
    Create an input stream from a filename or web page name.
  - In
```
public In(Scanner scanner)
```
    Create an input stream from a given Scanner source; use with new Scanner(String) to read from a string.
    Note that this does not create a defensive copy, so the scanner will be mutated as you read on.
- Method Detail
  - exists
```
public boolean exists()
```
    Does the input stream exist?
  - isEmpty
```
public boolean isEmpty()
```
    Is the input empty (except possibly for whitespace)? Use this to know whether the next call to readString(), readDouble(), etc will succeed.
  - hasNextLine
```
public boolean hasNextLine()
```
    Does the input have a next line? Use this to know whether the next call to readLine() will succeed.
    Functionally equivalent to hasNextChar().
  - hasNextChar
```
public boolean hasNextChar()
```
    Is the input empty (including whitespace)? Use this to know whether the next call to readChar() will succeed.
    Functionally equivalent to hasNextLine().
  - readLine
```
public String readLine()
```
    Read and return the next line.
  - readChar
```
public char readChar()
```
    Read and return the next character.
  - readAll
```
public String readAll()
```
    Read and return the remainder of the input as a string.
  - readString
```
public String readString()
```
    Read and return the next string.
  - readInt
```
public int readInt()
```
    Read and return the next int.
  - readDouble
```
public double readDouble()
```
    Read and return the next double.
  - readFloat
```
public float readFloat()
```
    Read and return the next float.
  - readLong
```
public long readLong()
```
    Read and return the next long.
  - readShort
```
public short readShort()
```
    Read and return the next short.
  - readByte
```
public byte readByte()
```
    Read and return the next byte.
  - readBoolean
```
public boolean readBoolean()
```
    Read and return the next boolean, allowing case-insensitive "true" or "1" for true, and "false" or "0" for false.
  - readAllStrings
```
public String[] readAllStrings()
```
    Read all strings until the end of input is reached, and return them.
  - readAllInts
```
public int[] readAllInts()
```
    Read all ints until the end of input is reached, and return them.
  - readAllDoubles
```
public double[] readAllDoubles()
```
    Read all doubles until the end of input is reached, and return them.
  - close
```
public void close()
```
    Close the input stream.
  - readInts
```
public static int[] readInts(String filename)
```
    Deprecated. Clearer to use new In(filename).readAllInts()
    
    Reads all ints from a file
  - readDoubles
```
public static double[] readDoubles(String filename)
```
    Deprecated. Clearer to use new In(filename).readAllDoubles()
    
    Reads all doubles from a file
  - readStrings
```
public static String[] readStrings(String filename)
```
    Deprecated. Clearer to use new In(filename).readAllStrings()
    
    Reads all strings from a file
  - readInts
```
public static int[] readInts()
```
    Deprecated. Clearer to use StdIn.readAllInts()
    
    Reads all ints from stdin
  - readDoubles
```
public static double[] readDoubles()
```
    Deprecated. Clearer to use StdIn.readAllDoubles()
    
    Reads all doubles from stdin
  - readStrings
```
public static String[] readStrings()
```
    Deprecated. Clearer to use StdIn.readAllStrings()
    
    Reads all strings from stdin
  - main
```
public static void main(String[] args)
```
    Test client.

Class In

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

In

In

In

In

In

In

Method Detail

exists

isEmpty

hasNextLine

hasNextChar

readLine

readChar

readAll

readString

readInt

readDouble

readFloat

readLong

readShort

readByte

readBoolean

readAllStrings

readAllInts

readAllDoubles

close

readInts

readDoubles

readStrings

readInts

readDoubles

readStrings

main