Multiple references in function parameters and return values ​​of Golang functions

Golang is a strongly typed static language that supports functional programming. It is designed to improve the efficiency of program operation and make it easy to develop and maintain. In Golang, a function can have multiple parameters and return values, and these parameters and return values ​​can be of different types or reference types. This article will introduce multiple references in function parameters and return values ​​of Golang functions.

In Golang, a function can have multiple parameters and return values, which allows developers to flexibly combine and pass data. Among the parameters of a function, if there are multiple parameters of reference types, these references will be passed to the function in the form of addresses. In the return value of a function, if multiple return values ​​are reference types, these references will be returned to the outside of the function in the form of pointers.

The following is an example showing multiple parameters and return values ​​​​of functions in Golang:

func add(a, b int) (int, int, int) {
    return a + b, a - b, a * b
}

func main() {
    sum, sub, mul := add(3, 2)
    fmt.Printf("sum = %d, sub = %d, mul = %d
", sum, sub, mul)
}

In the above code, the add function has two Parameters of type int and three return values ​​of type int. In the main function, we store the three parameters returned by the add function into sum, sub and ## respectively through assignment statements. #mul variable and print the output.

In addition to basic types, Golang also provides composite types such as pointer types and slice types. Among the parameters and return values ​​of a function, if there are multiple parameters or return values ​​that are composite types, then these composite types can be reference types or value types. If they are reference types, they will be passed or returned as pointers, which means they can change the original data inside or outside the function. If they are value types, they will be copied, mutating the copy of the original data inside or outside the function.

The following is an example showing composite types in multiple parameters and return values ​​of functions in Golang:

func modify(arr []int, ptr *int) ([]int, *int, int) {
    arr[0] = arr[0] * 2
    *ptr = *ptr * 2
    return arr, ptr, len(arr)
}

func main() {
    arr := []int{1, 2, 3}
    ptr := new(int)
    *ptr = 4
    resArr, resPtr, resLen := modify(arr, ptr)
    fmt.Printf("resArr = %v, resPtr = %d, resLen = %d
", resArr, *resPtr, resLen)
    fmt.Printf("arr = %v, ptr = %d
", arr, *ptr)
}

In the above code, the

modify function has a A slice type parameter and a pointer type parameter, as well as a slice type return value, a pointer type return value, and an integer return value. Inside the modify function, it first multiplies the first element of the slice by 2, then multiplies the value pointed to by the pointer by 2, and finally returns the modified slice, pointer, and length of the slice as the return value Return outside the function.

In the

main function, we create a slice arr and a pointer ptr, and set the first of arr Initialize an element to 1, initialize the value pointed to by ptr to 4, then call the modify function, and store the return value in resArr, ## respectively. #resPtr and resLen variables. Finally, we print out the values ​​of resArr, resPtr and resLen, as well as arr and ptr## to the console. # value. It can be seen from the results that the first element of arr is modified to 2, and the value of ptr is modified to 8. This is because the modify function is modified internally. their values. In short, in Golang, a function can have multiple parameters and return values, and these parameters and return values ​​can be of different types, and they can be reference types or value types. If they are reference types, they will be passed or returned as pointers, which allows them to modify the original data inside or outside the function. If they are value types, they will be copied, but the original data will not be affected. Proficiency in multiple parameters and return values ​​of functions is very useful for writing efficient, flexible and easy-to-maintain Golang functions.

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