public static void main(String[] args) throws IOException { System.out

Uso de System.in.read()
ReadCharacter.java
// la clase IOException pertenece a java.io
import java.io.*;
public class ReadCharacter {
public static void main(String[] args) throws IOException {
System.out.print("Enter character: ");
// System.in.read() throws an IOException,
// which the method calling it -- main --- throws back
// we don't worry about this for now!!
char c = (char) System.in.read();
System.out.println("\nYou entered: " + c);
}
}
EOF
ReadCharacters1.java
// la clase IOException pertenece a java.io
import java.io.*;
// this program must be executed under a DOS windows (not netbeans)
// as EOF (Ctrl-Z) doesn't work in Netbeans output window
class ReadCharacters1 {
public static void main(String args[]) throws IOException {
String cadena = "";
System.out.println("Enter characters (Ctrl-Z on new line to finish)!!");
// the Ctrl-Z command will only work in a DOS window,
// not in Scite environment (or netBeans)
int c = System.in.read();
while (c != -1) {
cadena = cadena + (char)c;
c = System.in.read();
}
// the method trim remove the blanks at the end of a string
System.out.println("You typed in: [" + cadena.trim() + "]" );
}
}
System.in.read() e IOException
ReadCharacters0.java
Gestión de Excepciones
ReadCharacters2.java
// la clase IOException pertenece a java.io
import java.io.*;
// en vez de lanzar la excepción lanzada por System.in.read()
// fuera del main (como en ReadCharacter2)
// atrapamos el error y imprimimos un mensaje
class ReadCharacters2 {
public static void main(String args[]) {
try {
String cadena = "";
System.out.println("Enter characters (Ctrl-Z on new line to finish)!!");
int c = System.in.read();
while (c != -1) {
cadena = cadena + (char)c;
c = System.in.read();
}
System.out.println("You typed in: [" + cadena.trim() + "]" );
} catch (IOException ioe) {
System.out.println("Problem reading character from the standard input.");
}
}
Leer línea por línea del flujo estándar de entrada
SystemIn.java
import java.io.*;
class SystemIn {
public static void main(String[] args) throws IOException {
String line;
InputStreamReader s = new InputStreamReader(System.in);
BufferedReader stdin = new BufferedReader(s);
System.out.print("Enter your input: ");
line = stdin.readLine();
System.out.println( "You typed: " + line );
s.close();
stdin.close();
}
}
Sumar diez números entrados por el flujo estándar
SumarDiez.java
import java.io.*;
class SumarDiez {
public static void main(String[] args) throws IOException {
String line;
InputStreamReader s = new InputStreamReader(System.in);
BufferedReader stdin = new BufferedReader(s);
int count = 1;
int sum = 0;
System.out.println("Please introduce numbers, one per line.");
while (count <= 10) {
// System.out.println("Enter number " + count + ":");
line = stdin.readLine();
sum = sum + Integer.parseInt(line.trim());
count++;
}
System.out.println("You typed in 10 numbers. The sum of the numbers is " + sum);
s.close();
stdin.close();
}
}
Sumar N números entrados por el flujo estándar
Sumar.java
import java.io.*;
class Sumar {
public static void main(String[] args) throws IOException {
System.out.println("Please introduce numbers, one per line.");
String line;
InputStreamReader s = new InputStreamReader(System.in);
BufferedReader stdin = new BufferedReader(s);
int sum = 0;
line = stdin.readLine();
while (line != null) {
sum = sum + Integer.parseInt(line.trim());
line = stdin.readLine();
}
System.out.println("The sum of the numbers is " + sum);
s.close();
stdin.close();
}
}