Java Source Codes

read numbers and strings

package corejava;

/**
An easy interface to read numbers and strings from
standard input

*/

public class Console
{ /**
print a prompt on the console but don't print a newline

@param prompt the prompt string to display
*/

public static void printPrompt(String prompt)
{ System.out.print(prompt + " ");
System.out.flush();
}

/**
read a string from the console. The string is
terminated by a newline

@return the input string (without the newline)
*/

public static String readLine()
{ int ch;
String r = "";
boolean done = false;
while (!done)
{ try
{ ch = System.in.read();
if (ch < 0 '' (char)ch == '\n')
done = true;
else if ((char)ch != '\r') // weird--it used to do \r\n translation
r = r + (char) ch;
}
catch(java.io.IOException e)
{ done = true;
}
}
return r;
}

/**
read a string from the console. The string is
terminated by a newline

@param prompt the prompt string to display
@return the input string (without the newline)
*/

public static String readLine(String prompt)
{ printPrompt(prompt);
return readLine();
}

/**
read an integer from the console. The input is
terminated by a newline

@param prompt the prompt string to display
@return the input value as an int
@exception NumberFormatException if bad input
*/

public static int readInt(String prompt)
{ while(true)
{ printPrompt(prompt);
try
{ return Integer.valueOf
(readLine().trim()).intValue();
} catch(NumberFormatException e)
{ System.out.println
("Not an integer. Please try again!");
}
}
}

/**
read a floating point number from the console.
The input is terminated by a newline

@param prompt the prompt string to display
@return the input value as a double
@exception NumberFormatException if bad input
*/

public static double readDouble(String prompt)
{ while(true)
{ printPrompt(prompt);
try
{ return Double.parseDouble(readLine().trim());
} catch(NumberFormatException e)
{ System.out.println
("Not a floating point number. Please try again!");
}
}
}
}

<<<----- Return to Java Source Code Questions Page.

Have a Question ? post your questions here. It will be answered as soon as possible.