Golang formal parameter requirements guide: parameter passing methods, value passing and address passing

Golang formal parameter requirements guide: parameter passing method, value passing and address passing

In the process of learning the Golang programming language, understand the parameter passing method and the value passing and address passing method. The concept of address transfer is very important. This article will delve into the formal parameter requirements in Golang, including the difference between parameter passing methods, value passing and address passing, and provide specific code examples to help readers better understand.

1. Parameter passing method

In Golang, there are two ways to pass function parameters: passing by value and passing by address.

1. Passing by value (passing a copy): When the function is called, the value of the actual parameter will be copied and passed to the formal parameter. Modifications to the formal parameter within the function will not affect the actual parameter itself.
2. Pass-by-address (pass pointer): When a function is called, the address of the actual parameter will be passed to the formal parameter. Modifications to the formal parameter within the function will affect the actual parameter itself.

2. The difference between passing by value and passing by address

• Passing by value:

  package main
  
  import "fmt"
  
  func changeValue(num int) {
    num = 10
  }
  
  func main() {
    x := 5
    changeValue(x)
    fmt.Println(x) // 输出结果为5
  }

is above In the code example, the formal parameter num is modified in the changeValue function, but the value of the actual parameter x does not change because the value passing method only operates on a copy of the actual parameter.

• Address method:

  package main
  
  import "fmt"
  
  func changeValue(num *int) {
    *num = 10
  }
  
  func main() {
    x := 5
    changeValue(&x)
    fmt.Println(x) // 输出结果为10
  }

In this code example, the changeValue function receives a formal parameter of pointer type, passing *num The actual parameter x is modified, and finally the value of the actual parameter x is changed.

3. Summary

Through the above code examples and explanations, readers can clearly understand the way parameters are passed in Golang and the difference between passing by value and passing by address. In actual programming, it is very important to choose the appropriate parameter transfer method according to specific needs, which can effectively improve program performance and reduce unnecessary memory overhead.

I hope this article can help readers better understand the parameter passing method in Golang and apply this knowledge in daily programming practice. If you have any questions or want to know more, please feel free to leave a message and I will try my best to answer your questions.

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