BigInteger

[Robbie Harjes]

BigInteger's are fun!, not. To set up some initial values for some BigInteger testing...

 BigInteger Y = 7; 

doesn't work... So what is the "standard" format? (The best conclusion I've come to is that there not exactly standardized, seeing how the length can change..? i don't know) And how do I convert/cast/whatever method I need for this to work:

 
int x = 7;
BigInteger Y = x; 

Thanks.

[Joe Pluta]

BigInteger and its sibling BigDecimal are objects, and so you create them using the "new" keyword:
BigInteger myBI = new BigInteger(7);
BigDecimal myBD = new BigDecimal(1.23);
Joe

[Marilyn de Queiroz]

Check out the methods of the BigInteger class to find out how to convert from an int to a BigInteger and back again (although if the number will fit into an int, I wonder why you would want to use BigInteger).
[ December 01, 2003: Message edited by: Marilyn de Queiroz ]

[Robbie Harjes]

Well thanks for the help... But I've come down to just 2 compile time errors. Here's the source code for the program (It's only to find the mod function [remainder] of very large exponential monomials.)

  
import java.math.*;
public class mymath {
  public static void main(String args[]) {
  int Y = 7;
  int A = 3;
  int P = 11;
  BigInteger big = new BigInteger(Y);
  big = big.pow(A);
  int returns = BigInteger.intValue(big.mod(P));
  }
}

I changed some of the code... realized that the values Y and A are going to be small, but it's only the result of Y^A that requires the BigInteger.
Finally, here are the compile-time errors:

  
mymath.java:11: BigInteger(long) has private access in java.math.BigInteger
  BigInteger big = new BigInteger(7);
                   ^
mymath.java:16: mod(java.math.BigInteger) in java.math.BigInteger cannot be applied to (int)
  int returns = BigInteger.intValue(big.mod(P));
                                       ^
2 errors

[ December 01, 2003: Message edited by: Robbie Harjes ]

[fred rosenberger]

Forgive me, but what am i missing??? i don't see a constructor for BigInteger that accepts an int. i think that's what the compiler is complaining about.
you can pass it a string...
BigInteger big = new BigInteger("7");
that seems to fix one error...
the other is that BigInter.mod() takes a BigInteger, not a long...
and then...
intvalue doesn't take any parameter, you just call it on your BigInteger object you want the value of...
integer i = big.intvalue();