golang * and &

In Golang, the * and & operators are used for pointers.

1. The * Operator:
   In Go, the * is used as a dereferencing operator or indirection operator. It gives you access to the value the pointer points to. If var is a pointer, then *var is the value stored in the location in memory that var points to.

Example:

package main

import "fmt"

func main() {
    var count = 5
    var ptr = &count
    fmt.Printf("count=%d\n", *ptr)
}

2. The & Operator:
   The & operator is used to get the address of a variable. When placed before a variable, it returns a pointer to the variable. This is called the "address of" operator.

Example:

package main

import "fmt"

func main() {
    var count = 5
    fmt.Printf("count=%d\n", count)
    fmt.Printf("address of count=%p\n", &count)
}

In this example, &count will give you the memory address where the variable count is stored.

In function parameters, * is used to indicate that the function expects a pointer to the data type, not the actual value of the data type.

Here's an example:

package main

import "fmt"

func increment(x *int) {
    *x++
}

func main() {
    var count = 5
    increment(&count)
    fmt.Println(count)  // Output: 6
}

In this example, the increment function takes a pointer to an integer. Inside the function, *x++ increments the value at the memory address x points to.

On the other hand, & is used in the function call (not in the function parameter type) to pass the address of the variable to the function, because the function expects a pointer.

If you tried to pass count (not &count) to increment, you'd get a compile error, because increment expects an *int (a pointer to an integer), not an int.

So in function parameter types, * indicates the function expects a pointer, and & is used in function calls to pass a pointer to a function that expects one.