Answer:
No. Integer and floating point types use different bit patterns to represent values.
No. Integer and floating point types use different bit patterns to represent values.
double from the KeyboardThe scheme used to represent integers is completely different from the scheme used to represent floating point. Even though you might regard 221 and 221.0 as equivalent, the bit patterns that they use are completely different.
Here is the 64-bit pattern that represents 221 using data type long
(the spaces are not part of the pattern):
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 1101 1101
Here is the 64-bit pattern that represents 221.0 using data type double:
0100 0000 0110 1011 1010 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
And here is the 64-bit pattern for the four characters " 221"
0000 0000 0010 0000 0000 0011 0010 0000 0000 0011 0010 0000 0000 0011 0000 0001
Scanner does floating point input
in a way similar to integer input.
Use a Scanner object to scan through a stream of
input characters and to convert them into a float or a double.
The methods that do this are nextFloat() and nextDouble().
Here is a program that inputs a string of characters and
converts that string
into primitive type double.
The value is multiplied the by two,
and then the original value and its double are
converted back into characters and written to the screen.
import java.io.*;
import java.util.Scanner;
class DoubleDouble
{
public static void main (String[] args)
{
double value;
Scanner scan = new Scanner( System.in );
System.out.print("Enter a double:");
value = scan.nextDouble();
System.out.println("value: " + value +" twice value: " + 2.0*value );
}
}
The program writes:
C:\temp>java DoubleDouble Enter a double: 3.14 value: 3.14 twice value: 6.28
It would be worth your effort to copy this program to a file and to compile and run it.
What do you suppose happens if the user types in
an integer value, like 211?