Problem with BigInteger

[Chaturaka Gunatilaka]

import java.math.BigInteger;
public class KillerCode{
	public static void main(String[]args){
		BigInteger sum=null;
		for(int i=1;i<=1000;i++){
			
			sum=sum+Math.pow(i, i);
			System.out.println(sum);
			
		}
	    
		
	}
}

When I try to run this code the following error message is coming up.
"The operator + is undefined for the argument type(s) BigInteger,double."
How can I solve this?
Thank you.

[Ulf Dittmer]

You need to use methods of the BigInteger class to add something to a BigInteger; "+" won't work.

[Chaturaka Gunatilaka]

Can you give me the code of that?I've tried but failed to solve.

[Jeff Verdegan]

Chaturaka Gunatilaka wrote:Can you give me the code of that?I've tried but failed to solve.

That's not how it works. If you show your work and TellTheDetails(←click) of what went wrong, people will be happy to guide you toward solving your own problem.

[Chaturaka Gunatilaka]

Jeff Verdegan wrote:

Chaturaka Gunatilaka wrote:Can you give me the code of that?I've tried but failed to solve.

That's not how it works. If you show your work and TellTheDetails(←click) of what went wrong, people will be happy to guide you toward solving your own problem.

ok then.

import java.math.BigInteger;
public class AWords{ public static void main(String[]args){
BigInteger sum=null; //BigInteger sum=new BigInteger(null);
for(int i=1;i<=1000;i++){
sum = sum.add(Math.pow(i, i));
System.out.println(sum);
}
}
}
So this is what I've done.but I got an error saying
Exception in thread "main" java.lang.Error: Unresolved compilation problem: The method add(BigInteger) in the type BigInteger is not applicable for the arguments (double) at AWords.main(AWords.java:5)

[Jeff Verdegan]

The error message is telling you exactly what's wrong. Math.pow() returns a double, but BigInteger's methods (not surprisingly) don't deal with doubles. BigInteger has its own pow() method that you should use. And in any case, you can't fit 1000^1000 into a double anyway.

You've got another problem:

BigInteger sum=null; //BigInteger sum=new BigInteger(null); 
 for(int i=1;i<=1000;i++){ 
 sum = sum.add(Math.pow(i, i));

The first time through the loop, what do you think is going to happen when you do sum.add? What is the value of sum the first time you do that?

[Winston Gutkowski]

Jeff Verdegan wrote:The first time through the loop, what do you think is going to happen when you do sum.add? What is the value of sum the first time you do that?

@Chaturaka - Hint: If your 'sum' field was an int instead of a BigInteger, what would you initialize it to?

Winston

[Campbell Ritchie]

You ought not to use Math.pow, because a double will probably run out of range before you reach the 1000th power, unless your value is 0 or ±1.