Go's '*' Modifier: Pass-by-Value or Pass-by-Reference?

Passing by Reference and Value in Go: Understanding the "*" Modifier

Passing data to and from functions is a fundamental aspect of programming. In Go, there are two main ways to do this: passing by value or passing by reference. The latter involves the use of the "*" modifier, which can be confusing for beginners.

In Java, passing an object by reference is straightforward, as objects are inherently passed as references. However, in Go, which allows both pass-by-value and pass-by-reference, using pointers can be more efficient.

The "" denotes a pointer to the type. For example, func PutTasks(db sql.DB) indicates that the db parameter is a pointer to an sql.DB object. The reason for this is that Go technically supports only pass-by-value, and passing a pointer is a way to simulate pass-by-reference.

When you pass a pointer, you are passing a value (the pointer itself) that points to the actual object in memory. This means that changes made to the object through the pointer will be reflected in the original variable passed to the function. On the other hand, passing a value directly (without "*") makes a copy of the original value, so changes made in the function won't affect the original variable.

The example provided, func PrintPerson(p *Person), requires a pointer because it needs to modify the Person object to print its details. If it received a value instead, any changes would only affect the copy held within the function.

Understanding pass-by-reference and pass-by-value is crucial for effective code writing in Go. Using pointers when appropriate can improve performance and maintain consistency between functions and caller code.

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