Pointers

Go supports pointers, allowing values of variables and records to be passed within the program by reference.

// zeroval has an int parameter, so arguments will be passed to it by value
// i.e. will get a copy of n distinct from the one in the calling function
func zeroval(n int) {
  n = 0
}
// zeroptr in contrast has an *int parameter, meaning that it takes an int
// pointer, i.e. the address of the of the value from the n variable in the
// calling function, also known as passing by reference
// the *n code in the function body **dereferences** the pointer from its memory
// address to the current value at that address
func zeroptr(n *int) {
  *n = 0
}

Assigning a value to a dereferenced pointer changes the value at the referenced address. The syntax &varName gives the memory address of varName, i.e. the pointer to varName