What is the default value of a variable in Go?

In Go, when variables are declared without explicit initialization, they are assigned default values, which are also known as zero values. Different types of variables have different zero values:

• Integer types (int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64) have a zero value of 0.
• Floating-point types (float32, float64) also have a zero value of 0.
• Boolean types (bool) have a zero value of false.
• String types (string) have a zero value of the empty string "".
• For pointer types, the zero value is nil.
• Slice, map, and channel types also have a zero value of nil.
• For arrays, each element is initialized to the zero value of its element type.
• For structs, each field is initialized to the zero value of its field type.

For example, if we declare the following variables:

go
var a int
var b float64
var c bool
var d string
var e *int

In this example, variables a and b default to 0, c defaults to false, d defaults to the empty string "", and e defaults to nil. These default values ensure that variables have a well-defined state before use, helping to reduce errors such as nil pointers or uninitialized values in the program.