mike adams - 1 year ago 107

Java Question

How do I solve the following?

- Calculate X^Y without Big Integer or Big Number.
- Need to print all digits e.g. 2^64 = 18446744073709551616.

I have written code in Java, but I am not getting the exact result for higher digits.

My code:

`public class Calculation {`

ArrayList<Double> c = new ArrayList<Double>();

double a = 2;

double b = 64;

double[] d = new double[5];

public void powerCalculation()

{

d[0] = java.lang.Math.pow(a, b);

System.out.println(d[0]);

}

public static void main(String[] args)

{

Calculation calculation = new Calculation();

calculation.powerCalculation();

}

}

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Answer Source

The mantissa of double isn't long enough to hold the digits of `2^64`

.
The straightforward but hard way would be using something like

```
ArrayList<Byte> a;
```

(where `a.get(x)`

means the value of position `10^x`

) and rewrite the algorithms of add, multiply and power you learned at school.

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