Returning Values from a Function
When a function needs to hand a result back to its caller, you
must:
- Declare the type of the value it will return (for example int, string, and so on) immediately after the parameter list.
- Include a return statement inside the function body to send the desired value back.
Template:
func FunctionName(param1 type, param2 type) returnType {
// perform operations here
return value
}
// perform operations here
return value
}
Example 1:
package main
import "fmt"
// add returns the sum of two integers.
func add(x, y int) int {
return x + y
}
func main() {
fmt.Println(add(1, 2))
}
import "fmt"
// add returns the sum of two integers.
func add(x, y int) int {
return x + y
}
func main() {
fmt.Println(add(1, 2))
}
Example 2:
package main
import "fmt"
// sum demonstrates a named return value.
// The returned integer is named `total`, so we can use a “naked”
return.
func sum(a, b int) (total int) {
total = a + b
return
}
func main() {
fmt.Println(sum(1, 2))
// Output: 3
}
Example 3:
package main
import "fmt"
// add returns the sum of x and y.
func add(x, y int) (sum int) {
sum = x + y
return
// naked return: 'sum' is returned automatically
}
func main() {
fmt.Println(add(1, 2))
}
Storing Return Values in Variables
- In Go, you can store a function's return value in a variable.
Example:
Here, the return value is stored in a variable named total:
package main
import "fmt"
func myFunction(x int, y int) (result int) {
result = x + y
return
}
func main() {
total := myFunction(1,
2)
fmt.Println(total)
}
Multiple Return Values
- Go functions can return more than one value.
Example:
This function returns an integer and a string:
package main
import "fmt"
func myFunction(x int, y string) (int, string) {
return x + x, y + "
World!"
}
func main() {
fmt.Println(myFunction(5, "Hello"))
}
Output:
10 Hello World!
Storing Multiple Return Values
- You can store multiple return values in separate variables:
Example:
package main
import "fmt"
func myFunction(x int, y string) (int, string) {
return x + x, y + "
World!"
}
func main() {
a, b := myFunction(5,
"Hello")
fmt.Println(a, b)
}
Output:
10 Hello World!
Ignoring Return Values
- If you don’t need all return values, use an underscore (_) to ignore one.
Example: Ignore the first value
package main
import "fmt"
func myFunction(x int, y string) (int, string) {
return x + x, y + "
World!"
}
func main() {
_, b := myFunction(5,
"Hello")
fmt.Println(b)
}
Output:
Hello World!
Example: Ignore the second value
package main
import "fmt"
func myFunction(x int, y string) (int, string) {
return x + x, y + "
World!"
}
func main() {
a, _ := myFunction(5,
"Hello")
fmt.Println(a)
}
Output:
10
More topic in Go
