Go: What is the difference between pointer and value receiver in Go?

Pointer receiver — can modify. Value receiver — works on copy.

*Pointer receiver (T):

• Can modify original.
• Avoids copying.
• Use for large structs.

1type Counter struct {
2    count int
3}
4
5// Pointer receiver — can modify
6func (c *Counter) Increment() {
7    c.count++  // Modifies original
8}

Value receiver (T):

• Works on copy.
• Cannot modify original.
• Good for small structs.

1type Point struct {
2    X, Y int
3}
4
5// Value receiver — works on copy
6func (p Point) Distance() float64 {
7    return math.Sqrt(float64(p.X*p.X + p.Y*p.Y))
8}

Guidelines:

• Use pointer if method modifies receiver.
• Use pointer if struct is large.
• Use value if struct is small and immutable.
• Be consistent.