# Golang math.Copysign() Function with Examples

Golang | math.Copysign() Function: Here, we are going to learn about the Copysign() function of the math package with its usages, syntax, and examples.
Submitted by IncludeHelp, on August 29, 2021

## math.Copysign()

The Copysign() function is an inbuilt function of the math package which is used to get a value with the magnitude of x and the sign of y. Where, x is the first parameter, and y is the second parameter.

It accepts two parameters and returns a value with the magnitude of x and the sign of y.

Syntax:

```func Copysign(x, y float64) float64
```

Parameter(s):

• x, y : The values whose magnitude and sign are to be copied.

Return Value:

The return type of Copysign() function is a float64, it returns a value with the magnitude of x and the sign of y.

Example 1:

```// Golang program to demonstrate the
// example of math.Copysign() Function

package main

import (
"fmt"
"math"
)

func main() {
fmt.Println(math.Copysign(1.49, -2))
fmt.Println(math.Copysign(2.50, 3.5))
fmt.Println(math.Copysign(-2.51, 2.3))

fmt.Println(math.Copysign(1, 0))
fmt.Println(math.Copysign(1, 0))
fmt.Println(math.Copysign(-1, -1))
}
```

Output:

```-1.49
2.5
2.51
1
1
-1
```

Example 2:

```// Golang program to demonstrate the
// example of math.Copysign() Function

package main

import (
"fmt"
"math"
)

func main() {
var x float64
var y float64
var CopysignXY float64

x = 1.49
y = -2.5
CopysignXY = math.Copysign(x, y)
fmt.Println("Copysign(", x, ",", y, ") = ", CopysignXY)

x = -1.49
y = 2.5
CopysignXY = math.Copysign(x, y)
fmt.Println("Copysign(", x, ",", y, ") = ", CopysignXY)

x = -1.49
y = -2.5
CopysignXY = math.Copysign(x, y)
fmt.Println("Copysign(", x, ",", y, ") = ", CopysignXY)

x = 1
y = 0
CopysignXY = math.Copysign(x, y)
fmt.Println("Copysign(", x, ",", y, ") = ", CopysignXY)
}
```

Output:

```Copysign( 1.49 , -2.5 ) =  -1.49
Copysign( -1.49 , 2.5 ) =  1.49
Copysign( -1.49 , -2.5 ) =  -1.49
Copysign( 1 , 0 ) =  1
```