Số lớn (BigInt)

let bn = 75n
console.log(bn.toString(10))
 
bn = BigInt('75')
console.log(bn.toString(10))
 
bn = BigInt(0x4b)
console.log(bn.toString(10))
 
bn = BigInt('0x4b')
console.log(bn.toString(10))
 
bn = BigInt('0x' + Buffer.from('4b', 'hex').toString('hex'))
console.log(bn.toString(10))
console.log(Number(bn))
console.log(bn.toString(16))
console.log(Buffer.from(bn.toString(16), 'hex'))
 
let bn2 = BigInt(100)
let isEqual = bn === bn2
console.log(isEqual)
 
let isGreater = bn > bn2
console.log(isGreater)
 
let isLesser = bn < bn2
console.log(isLesser)

package main
 
import (
	"encoding/hex"
	"fmt"
	"math/big"
)
 
func main() {
	bn := new(big.Int)
	bn.SetUint64(75)
	fmt.Println(bn.String())
 
	bn = new(big.Int)
	bn.SetString("75", 10)
	fmt.Println(bn.String())
 
	bn = new(big.Int)
	bn.SetUint64(0x4b)
	fmt.Println(bn.String())
 
	bn = new(big.Int)
	bn.SetString("4b", 16)
	fmt.Println(bn.String())
 
	bn = new(big.Int)
	bn.SetBytes([]byte{0x4b})
	fmt.Println(bn.String())
	fmt.Println(bn.Uint64())
	fmt.Println(hex.EncodeToString(bn.Bytes()))
	fmt.Println(bn.Bytes())
 
	bn2 := big.NewInt(100)
	isEqual := bn.Cmp(bn2) == 0
	fmt.Println(isEqual)
 
	isGreater := bn.Cmp(bn2) == 1
	fmt.Println(isGreater)
 
	isLesser := bn.Cmp(bn2) == -1
	fmt.Println(isLesser)
}

// Cargo.toml: num-bigint = "0.5", num-traits = "0.2"
use num_bigint::{BigInt, Sign};
use num_traits::ToPrimitive;
 
fn main() {
    let mut bn: BigInt = 75u32.into();
    println!("{bn}");
 
    bn = "75".parse().unwrap();
    println!("{bn}");
 
    bn = 0x4bu32.into();
    println!("{bn}");
 
    bn = BigInt::parse_bytes(b"4b", 16).unwrap();
    println!("{bn}");
 
    bn = BigInt::from_bytes_be(Sign::Plus, &[0x4b]);
    println!("{bn}");
    println!("{}", bn.to_u64().unwrap());
    println!("{bn:x}");
    println!("{:?}", bn.to_bytes_be().1);
 
    let bn2 = BigInt::from(100);
    let is_equal = bn == bn2;
    println!("{is_equal}");
 
    let is_greater = bn > bn2;
    println!("{is_greater}");
 
    let is_lesser = bn < bn2;
    println!("{is_lesser}");
}

// Swift không có kiểu số nguyên lớn tuỳ ý trong stdlib/Foundation; các giá trị dưới đây đều nhỏ nên
// UInt64 là đủ. Cần số thực sự lớn thì phải dùng package ngoài (ví dụ attaswift/BigInt) qua SPM.
var bn: UInt64 = 75
print(String(bn))
 
bn = UInt64("75")!
print(String(bn))
 
bn = UInt64(0x4b)
print(String(bn))
 
bn = UInt64("4b", radix: 16)!
print(String(bn))
 
let bytes: [UInt8] = [0x4b]
bn = bytes.reduce(0) { $0 << 8 | UInt64($1) }
print(String(bn))
print(bn) // "Number(bn)": UInt64 đã là kiểu số, không cần chuyển đổi
print(String(bn, radix: 16))
print(bytes)
 
let bn2: UInt64 = 100
let isEqual = bn == bn2
print(isEqual)
 
let isGreater = bn > bn2
print(isGreater)
 
let isLesser = bn < bn2
print(isLesser)

void main() {
    BigInteger bn = BigInteger.valueOf(75);
    IO.println(bn.toString(10));
 
    bn = new BigInteger("75");
    IO.println(bn.toString(10));
 
    bn = BigInteger.valueOf(0x4b);
    IO.println(bn.toString(10));
 
    bn = new BigInteger("4b", 16);
    IO.println(bn.toString(10));
 
    bn = new BigInteger(1, new byte[] { 0x4b }); // signum = 1 (dương), giống SetBytes
    IO.println(bn.toString(10));
    IO.println(bn.longValue()); // Number(bn)
    IO.println(bn.toString(16));
    IO.println(Arrays.toString(bn.toByteArray()));
 
    BigInteger bn2 = BigInteger.valueOf(100);
    boolean isEqual = bn.equals(bn2);
    IO.println(isEqual);
 
    boolean isGreater = bn.compareTo(bn2) > 0;
    IO.println(isGreater);
 
    boolean isLesser = bn.compareTo(bn2) < 0;
    IO.println(isLesser);
}