README.md

go-biggier

a go lang big integer lib

refer to java BigInteger

In the go language, we know that there are only byte, int32, and int64 for integers, float have only float32 and float64. Sometimes we need to use large number operations according to your needs. The big package in go with NewInt and NewFloat, but there are fewer APIs, and only basic types can be used for initialization. You cannot use a string for initialization. So I developed go-bigger that reference to Java's large number classes and provided a rich API calls.

1. Import module

go get github.com/sineycoder/go-bigger

2. BigInteger

In BigInteger, we cached |x| < 16 BigInteger

you can use big_integer.NewBigIntegerInt(1231221) or big_integer.ValueOf(6782613786431) to initialize a BigInteger. If use ValueOf and within 16, it returns a cache BigInteger.

2.1 Add

func main() {
	a := bigger.BigIntegerValueOf(6782613786431)
	b := bigger.BigIntegerValueOf(-678261378231)
	res := a.Add(b)
	fmt.Println(res.String())
}

// result：6104352408200

2.2 Subtract

func main() {
	a := bigger.BigIntegerValueOf(6782613786431)
	b := bigger.BigIntegerValueOf(-678261378231)
	res := a.Subtract(b)
	fmt.Println(res.String())
}

// result：7460875164662

2.3 Divide

func main() {
	a := bigger.BigIntegerValueOf(6782613786431)
	b := bigger.BigIntegerValueOf(-678261378231)
	res := a.Divide(b)
	fmt.Println(res.String())
}

// result： -10

2.4 Multiply

func main() {
	a := bigger.BigIntegerValueOf(6782613786431)
	b := bigger.BigIntegerValueOf(-678261378231)
	res := a.Multiply(b)
	fmt.Println(res.String())
}

// result：-4600384974793271546583561

3.BigDecimal

you can use bigger.NewBigDecimalString("123123.111") or bigger.BigDecimalValueOf(6782613786431.111) to initialize a BigInteger. If use BigDecimalValueOf and whithin 10, it returns a chache BigDecimal.

3.1 Add

func main() {
	a := bigger.BigDecimalValueOf(6782613786431)
	b := bigger.BigDecimalValueOf(-678261378231)
	res := a.Add(b)
	fmt.Println(res.String())
}

// result：6104352408200

3.2 Subtract

func main() {
	a := bigger.BigDecimalValueOf(6782613786431)
	b := bigger.BigDecimalValueOf(-678261378231)
	res := a.Subtract(b)
	fmt.Println(res.String())
}

// result：7460875164662

3.3 Divide

func main() {
	a := bigger.BigDecimalValueOf(6782613786431)
	b := bigger.BigDecimalValueOf(-678261378231)
	res := a.Divide(b, 12, bigger.ROUND_HALF_UP)
	fmt.Println(res.String())
}

// result： -10.000000006076 

3.4 Multiply

func main() {
	a := bigger.BigDecimalValueOf(6782613786431)
	b := bigger.BigDecimalValueOf(-678261378231)
	res := a.Multiply(b)
	fmt.Println(res.String())
}

// result：-4600384974793271546583561

if you want to set a precision, you can use setScale(). Remenber: The return value must be assigned. (e.g. res = res.setScale(12, bigger.ROUND_HALF_UP))

The details please visit this WebSite:https://blog.csdn.net/a568283992/article/details/119698329