What is the difference between Go's local and global scope for variables and constants in Go programs?

In Go, variables and constants can be declared at different scopes within a program, such as local or global. The main difference between local and global scope is where the variable or constant can be accessed.

Variables or constants declared within a function have local scope, which means they can only be accessed within that function. For example:

func foo() {
    x := 1 // local variable
    // x can only be accessed within this function
}

On the other hand, variables or constants declared outside of any function or block have global scope, which means they can be accessed from any part of the program. For example:

var y int // global variable
const z = "hello" // global constant

func foo() {
    // y and z can be accessed from here
}

func bar() {
    // y and z can also be accessed from here
}

It's generally recommended to limit the use of global variables and constants in Go programs, as they can make it harder to reason about code and can introduce unexpected side effects. Instead, it's usually better to use function parameters and return values to pass data between functions.