Go: Default value of struct, string, slice, map

Variables declared without an explicit initial value are set to their zero values:

• false for booleans,
• 0 for integers,
• 0.0 for floats,
• "" for strings, and
• nil for pointers, functions, interfaces, slices, channels, and maps.

This initialization is done recursively; for example each element of an array of structs will have its fields zeroed if no value is specified.

var n int // n == 0

type T struct {
        n int
        f float64
        next *T
}
t := new(T) // t.n == 0, t.f == 0.0 and t.next == nil