Equality.java


Below is the syntax highlighted version of Equality.java from §9.1 Scientific Computation.



/******************************************************************************
 *  Compilation:  javac Equality.java
 *  Execution:    java Equality
 * 
 *  Not all integers can be represented exactly using floating point.
 *
 *  % java Equality
 *  16777217
 *  16777216.00000000000
 *  9007199254740993
 *  9007199254740992.00000000000
 *
 ******************************************************************************/
import java.text.DecimalFormat;

public class Equality {

    public static void main(String[] args) { 
       DecimalFormat df = new DecimalFormat("0.00000000000");

       int   x = 16777217;             // 2^24 + 1
       float y = 16777217;
       StdOut.println(x);
       StdOut.println(df.format(y));
       StdOut.println(x == y);
       StdOut.println(x == (int) y);
       StdOut.println();

       long   v = 9007199254740993L;   // 2^53 + 1
       double w = 9007199254740993L;
       StdOut.println(v);
       StdOut.println(df.format(w));
       StdOut.println(v == w);
       StdOut.println(v == (long) w);


   }

}


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Last updated: Fri Oct 20 14:12:12 EDT 2017.