Simulating Runs

runsim.go

package main

import (
	"fmt"
	"math/rand/v2"
	"os"
	"strconv"
	"sync"
)

func main() {
	trialsPerSim, err := strconv.Atoi(os.Args[1])
	simulations, err := strconv.Atoi(os.Args[2])
	chance, err := strconv.Atoi(os.Args[3])
	runLen, err := strconv.Atoi(os.Args[4])

	successes := 0

	if err != nil {
		panic(err)
	}

	var wg sync.WaitGroup

	for i := 0; i < simulations; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			simulate(trialsPerSim, chance, runLen, &successes)
		}()
	}

	wg.Wait()

	fmt.Println(float64(successes) / float64(simulations))
}

func simulate(trialsPerSim int, chance int, runLen int, successes *int) {
	streak := 0
	for i := 0; i < trialsPerSim; i++ {
		trial := rand.IntN(chance)
		if trial == (chance - 1) {
			streak += 1
		} else {
			streak = 0
		}
		if streak >= runLen {
			*successes += 1
			return
		}
	}
}