Go flashcards, generated for you.

Use `var name type` for explicit declaration, or `:=` for short declaration inside functions. Example: `var x int` or `x := 42`.

The default value assigned to uninitialized variables. For int/float: 0, for string: "", for bool: false, for pointers/slices/maps/channels: nil.

`var` can be used at package or function scope; `:=` only works inside functions and infers the type. Both declare and initialize, but `:=` is more concise.

If `i` was declared in an outer scope with `var`, you cannot redeclare it with `:=` in the inner scope. Use `i = i + 1` (assignment) instead.

`defer` postpones the execution of a function until the surrounding function returns. Deferred calls execute in LIFO order. Common use: file cleanup with `defer file.Close()`.

Functions return multiple values as a tuple. By convention, the last return value is an error: `func Foo() (int, error)`. Check with `if err != nil { ... }`.

A pointer holds the memory address of a value. Declare with `*Type`, get address with `&value`, dereference with `*pointer`. Example: `var p *int; p = &x; *p = 10`.

Slices are passed by value, but contain a pointer to the underlying array. Modifying slice contents affects the original, but reassigning the slice (length/capacity) does not. To modify the slice header itself, pass `*[]T`.

`new(T)` allocates zero-valued memory and returns `*T`. `make(T)` initializes slices, maps, and channels and returns `T`. Use `make` for these types, `new` for simple allocation.

A goroutine leaks if it's never scheduled to finish (e.g., blocked on a channel that never receives). Prevent by: closing channels, using timeouts with `context.WithTimeout`, or passing a done channel to signal completion.