func (r *RNG) Intn(n int) int {
	if n <= 0 {
		return 0
	}
	return int(r.Uint64n(uint64(n)))
}
// Intn returns an int uniformly in [0, n).
// Not safe for concurrent callers.
Intn returns an int uniformly in [0, n).
Not safe for concurrent callers.
// Intn returns an int uniformly in [ 0 n ) . // Not safe for concurrent callers .
func (r *RNG) Intn(n int) int {
	if n <= 0 {
		return 0
	}
	return int(r.Uint64n(uint64(n)))
}
func ( r * RNG ) Intn ( n int ) int { if n <= 0 { return 0 } return int ( r . Uint64n ( uint64 ( n ) ) ) }
Intn returns an int uniformly in [0, n).
Intn returns an int uniformly in [ 0 n ) .