M. Gallant 10/14/97
JDK1.1 includes two new classes for facilitating mathematical
computation with arbitrary-precision numbers: BigInteger
and BigDecimal. For further details, see the
JDK1.1 Documentation.
The example below shows a simple consecutive big-number multiplication example
implemented in a Java application. The user enters two arbitrary integers at the
command prompt. The integers are converted to BigInteger objects, multiplied and
the result is squared 5 consecutive times. Note that BigIntegers are automatically
made as large as necessary to accomodate calculation results. Note also that
the implied toString() conversion method is supported as expected for
the string concatenation operator in the println method. Java applications like
this can conveniently be launched from a DOS shortcut.
DOS System Output
Java Source Code
Java 1.1 Executable Bytecode
import java.math.BigInteger;
import java.io.* ;
public class bigintest {
public static void main(String args[]) throws IOException{
String I1, I2 ;
BigInteger b1, b2, b3 ;
PrintWriter dos = new PrintWriter(System.out, true) ;
System.out.println("\n\n") ;
System.out.println(" *************************************************");
System.out.println(" * ------------------------------------ *");
System.out.println(" * BigInteger Consecutive Multiplicaton *");
System.out.println(" * ------------------------------------ *");
System.out.println(" * *");
System.out.println(" * by M. Gallant 10/14/97 *");
System.out.println(" *************************************************");
System.out.println("\n\n");
BufferedReader disys = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter first integer (I1):") ;
I1=disys.readLine() ;
System.out.println("\nEnter second integer (I2):") ;
I2=disys.readLine() ;
b1 = new BigInteger(I1) ;
b2 = new BigInteger(I2) ;
b3 = b1.multiply(b2) ;
System.out.println("\n\n(I1 X I2) = " + b3) ;
b3=b3.multiply(b3) ; // Square the previous result.
System.out.println("\n\n(I1 X I2)^2 = " + b3) ;
b3=b3.multiply(b3) ; // Square the previous result.
System.out.println("\n\n(I1 X I2)^4 = " + b3) ;
b3=b3.multiply(b3) ; // Square the previous result.
System.out.println("\n\n(I1 X I2)^8 = " + b3) ;
b3=b3.multiply(b3) ; // Square the previous result.
System.out.println("\n\n(I1 X I2)^16 = " + b3) ;
b3=b3.multiply(b3) ; // Square the previous result.
System.out.println("\n\n(I1 X I2)^32 = " + b3) ;
disys.close() ;
}
}
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