Round a floating point number to a specified precision using the math.Round function

Use the math.Round function to round floating-point numbers to the specified precision

When performing floating-point number calculations, we often need to round the results to the specified precision. The math package in the Go language provides the Round function, which can easily implement this function. This article will introduce how to use the math.Round function to round floating point numbers to a specified precision and provide code examples.

The prototype of the math.Round function is as follows:

func Round(x float64) float64

The Round function receives a floating point number x as a parameter and returns a rounded to the nearest integer the result of. The result is a floating point number, the same type as x. If x is an integer, the Round function returns x directly without any modification. If x is a half integer (i.e. the decimal part is 0.5), then the Round function rounds it to the nearest even number. Otherwise, the Round function rounds x to the nearest integer.

In addition to the above-mentioned Round function, the math package also provides the RoundToEven function, which behaves basically the same as the Round function. The only difference is that for half integers, the RoundToEven function rounds them to the nearest even number. In this article, we mainly focus on the use of Round function.

Here is a simple example that shows how to use the math.Round function to round a floating point number to a specified precision:

package main

import (
    "fmt"
    "math"
)

func main() {
    x := 3.14159
    precision := 2

    rounded := math.Round(x*math.Pow(10, float64(precision))) / math.Pow(10, float64(precision))

    fmt.Printf("原始值：%f
", x)
    fmt.Printf("四舍五入到%d位小数：%f
", precision, rounded)
}

In the above example, we define a floating point number x and A precision precision. We first multiply x by 10 raised to the precision power and then call the Round function to round the result. Finally, we divide the result by 10 raised to the precision power to restore the original precision.

Execute the above code, the output is as follows:

Original value: 3.141590
Rounded to 2 decimal places: 3.14

As you can see, we successfully rounded the floating point number 3.14159 to 2 decimal places.

Summary:
Through the math.Round function, we can easily round floating point numbers to a specified precision. Before using the Round function, we need to perform appropriate multiplication and division operations to ensure the accuracy of the precision calculation. For more complex scenarios, we can also adjust and expand according to actual needs.

I hope this article will be helpful to you in using the math.Round function to round floating point numbers!

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