golang precision lost

Golang is a very popular programming language that is widely popular for its efficient and powerful features. However, when using Golang, you may encounter certain problems, one of which is loss of precision.

Some developers may think that Golang is a very suitable language for numerical calculations, but you are likely to encounter problems with loss of precision. So, how does the loss of precision occur?

First, let us understand floating point numbers. Golang uses the IEEE 754 standard to represent floating point numbers, that is, floating point numbers are represented as binary numbers with sign bits, exponents, and mantissas. This representation can represent very large or very small numbers very efficiently.

However, due to the limitations of this representation, Golang cannot accurately represent certain numbers. For example, when you try to convert 0.1 to binary, it produces an infinite loop of mantissas. Therefore, Golang will round this number, resulting in loss of precision.

The following is a sample code that demonstrates the problem of precision loss in Golang:

package main

import "fmt"

func main() {
    a := 0.1
    b := 0.2
    c := a + b
    fmt.Println(c)
}

In the above code, we add 0.1 and 0.2 and then print the result to the console. You might expect the output to be 0.3, but it's actually 0.30000000000000004.

This is because in Golang, neither 0.1 nor 0.2 can be accurately represented, so their addition result cannot be accurately represented either. The resulting number becomes inaccurate due to rounding errors.

While this example may not seem trivial, it can become a serious problem when high-precision calculations are required. For example, when doing financial calculations, accuracy is very important.

To solve this problem, we can use the exact number type in Golang. Golang provides a package called big, which contains some precise numeric types, such as Int and Float.

The following is a sample code to solve the above problem using big.Float:

package main

import (
    "fmt"
    "math/big"
)

func main() {
    a := big.NewFloat(0.1)
    b := big.NewFloat(0.2)

    c := new(big.Float).Add(a, b)

    fmt.Println(c)
}

In the above code, we created using big.NewFloat Two exact floating point numbers and then add them using the Add method. Finally, we print the result, this time the output is 0.3.

To summarize, although Golang is a powerful programming language, you may encounter problems with loss of precision when it comes to numerical calculations. To solve this problem, you can use exact numeric types in Golang. Remember, accuracy is very important when doing high-precision calculations.

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