go_by_example/random-numbers.go at master · pathbox/go_by_example · GitHub

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package main

import (
	"fmt"
	"math/rand"
	"time"
)

func main() {
	fmt.Print(rand.Intn(100), ",")
	fmt.Print(rand.Intn(100))
	fmt.Println()

	fmt.Println(rand.Float64())

	fmt.Print((rand.Float64()*5)+5, ",")
	fmt.Print((rand.Float64() * 5) + 5)
	fmt.Println()

	s1 := rand.NewSource(time.Now().UnixNano())
	r1 := rand.New(s1)

	fmt.Print(r1.Intn(100), ",")
	fmt.Print(r1.Intn(100))
	fmt.Println()
	// If you seed a source with the same number, it produces the same sequence of random numbers.
	s2 := rand.NewSource(42)
	r2 := rand.New(s2)
	fmt.Print(r2.Intn(100), ",")
	fmt.Print(r2.Intn(100))
	fmt.Println()
	s3 := rand.NewSource(42)
	r3 := rand.New(s3)
	fmt.Print(r3.Intn(100), ",")
	fmt.Print(r3.Intn(100))
}

// 81,87
// 0.6645600532184904
// 7.123187485356329,8.434115364335547
// 0,28
// 5,87
// 5,87