In Go, a constant is a value that cannot be changed during program execution. It can be declared using the const keyword followed by a name and a value, like so:
const pi = 3.14
Constants in Go can be of several types, including integers, floats, booleans, and strings. In addition to simple values, constants can also be expressions involving other constants or variables, as long as the result can be determined at compile time.
For example, the following is a valid constant expression:
const secondsInHour = 60 * 60
In this case, the expression
**60 * 60** is evaluated at compile time to produce the constant value
**3600**, which is then assigned to the constant
Constant values in Go are similar to variables in that they have a type and a value, but they differ in that their value cannot be changed once it has been assigned. This means that they can be used in places where a value needs to be fixed at compile time, such as array sizes or switch case expressions.
Overall, constant expressions and constant values in Go provide a way to define and use values that are known at compile time, and cannot be changed during program execution.