_result.txt

BenchmarkPrimeNumber1-4          2000000              1096 ns/op
BenchmarkPrimeNumber1-4          2000000              1089 ns/op
BenchmarkPrimeNumber1-4          2000000              1094 ns/op
BenchmarkPrimeNumber1-4          2000000              1089 ns/op
BenchmarkPrimeNumber1-4          2000000              1117 ns/op
BenchmarkPrimeNumber1-4          2000000              1123 ns/op
BenchmarkPrimeNumber1-4          2000000              1164 ns/op
BenchmarkPrimeNumber1-4          2000000              1091 ns/op
BenchmarkPrimeNumber1-4          2000000              1087 ns/op
BenchmarkPrimeNumber1-4          2000000              1094 ns/op
BenchmarkPrimeNumber2-4          2000000              1045 ns/op
BenchmarkPrimeNumber2-4          2000000              1038 ns/op
BenchmarkPrimeNumber2-4          2000000              1051 ns/op
BenchmarkPrimeNumber2-4          2000000              1035 ns/op
BenchmarkPrimeNumber2-4          2000000              1042 ns/op
BenchmarkPrimeNumber2-4          2000000              1038 ns/op
BenchmarkPrimeNumber2-4          2000000              1034 ns/op
BenchmarkPrimeNumber2-4          2000000              1119 ns/op
BenchmarkPrimeNumber2-4          2000000              1179 ns/op
BenchmarkPrimeNumber2-4          2000000              1038 ns/op
PASS
ok      github.com/mattn/go-sandbox/prime       59.978s

prime_test.go

package prime

import (
	"math"
	"testing"
)

func checkPrimeNumber1(n int) bool {
	for i := 2; i <= int(math.Sqrt(float64(n))); i++ {
		if int(n/i)*i == n {
			return false
		}
	}
	return true
}

func checkPrimeNumber2(n int) bool {
	if n <= 3 || n == 5 {
		return true
	}
	for i := 7; i <= int(math.Sqrt(float64(n))); i += 30 {
		if n%i == 0 || n%(i+4) == 0 || n%(i+6) == 0 || n%(i+10) == 0 ||
			n%(i+12) == 0 || n%(i+16) == 0 || n%(i+22) == 0 || n%(i+24) == 0 {
			return false
		}
	}
	return true
}

func BenchmarkPrimeNumber1(b *testing.B) {
	b.ResetTimer()
	for i := 2; i < b.N; i++ {
		checkPrimeNumber1(i)
	}
}

func BenchmarkPrimeNumber2(b *testing.B) {
	b.ResetTimer()
	for i := 2; i < b.N; i++ {
		checkPrimeNumber2(i)
	}
}