如何在Java中将int
与BigInteger
进行比较?我特别需要知道int
是否小于BigInteger
。这是我正在使用的代码:
private static BigInteger two = new BigInteger("2");
private static BigInteger three = new BigInteger("3");
private static BigInteger zero = new BigInteger("0");
public static BigInteger bigIntSqRootCeil(BigInteger x) throws IllegalArgumentException {
if (x.compareTo(BigInteger.ZERO) < 0) {
throw new IllegalArgumentException("Negative argument.");
}
if (x == BigInteger.ZERO || x == BigInteger.ONE) {
return x;
}
BigInteger two = BigInteger.valueOf(2L);
BigInteger y;
for (y = x.divide(two);
y.compareTo(x.divide(y)) > 0;
y = ((x.divide(y)).add(y)).divide(two));
if (x.compareTo(y.multiply(y)) == 0) {
return y;
} else {
return y.add(BigInteger.ONE);
}
}
private static boolean isPrimeBig(BigInteger n){
if (n.mod(two) == zero)
return (n.equals(two));
if (n.mod(three) == zero)
return (n.equals(three));
BigInteger m = bigIntSqRootCeil(n);
for (int i = 5; i <= m; i += 6) {
if (n.mod(BigInteger.valueOf(i)) == zero)
return false;
if(n.mod(BigInteger.valueOf(i + 2)) == zero)
return false;
};
return true;
};
感谢。
答案 0 :(得分:21)
如何在Java中将int与BigInteger进行比较?我特别需要知道int是否小于BigInteger。
在比较之前将int
变为BigInteger
:
if (BigInteger.valueOf(intValue).compareTo(bigIntegerValue) < 0) {
// intValue is less than bigIntegerValue
}
答案 1 :(得分:4)
而不是
if (x == BigInteger.ZERO || x == BigInteger.ONE) {
return x;
你应该使用: -
if (x.equals(BigInteger.ZERO) || x.equals(BigInteger.ONE)){
return x;
此外,您应该首先将Integer更改为BigInteger,然后在答案中进行比较,如Joe
所述:
Integer a=3;
if(BigInteger.valueOf(a).compareTo(BigInteger.TEN)<0){
// your code...
}
else{
// your rest code, and so on.
}
答案 2 :(得分:2)
只需使用BigInteger.compare
:
int myInt = ...;
BigInteger myBigInt = ...;
BigInteger myIntAsABigInt = new BigInteger(String.valueOf(myInt));
if (myBigInt.compareTo(myIntAsABigInt) < 0) {
System.out.println ("myInt is bigger than myBigInt");
} else if (myBigInt.compareTo(myIntAsABigInt) > 0) {
System.out.println ("myBigInt is bigger than myInt");
} else {
System.out.println ("myBigInt is equal to myInt");
}