first commit

.gitignore

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+createpairings

README.md

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+1. Write players separated by newline in players.txt
+2. Output can be redirected in a csv file: `./createpairings > results.csv`

go.mod

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+module git.artlef.pw/createpairings
+
+go 1.18

main.go

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+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+)
+
+type Match struct {
+	WhitePlayer string
+	BlackPlayer string
+}
+
+func getPlayerlist() []string {
+	var playerList []string
+	file, err := os.Open("players.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		playerList = append(playerList, scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+	return playerList
+}
+
+func main() {
+	playerList := getPlayerlist()
+	matchList := getMatchs(playerList)
+	printMatchList(matchList)
+	checkMatchList(matchList, playerList)
+}
+
+func getMatchs(playerList []string) []Match {
+	if len(playerList) == 0 {
+		return nil
+	}
+	var matchList []Match
+	subList := playerList[1:]
+	for i, player := range subList {
+		whitePlayer := playerList[0]
+		blackPlayer := player
+		if i%2 == 0 {
+			whitePlayer = player
+			blackPlayer = playerList[0]
+		}
+		matchList = append(matchList, Match{whitePlayer, blackPlayer})
+	}
+	return append(matchList, getMatchs(subList)...)
+}
+
+func printMatchList(matchList []Match) {
+	for _, match := range matchList {
+		fmt.Printf("%s,%s\n", match.WhitePlayer, match.BlackPlayer)
+	}
+}
+
+func checkMatchList(matchList []Match, playerList []string) {
+	for _, player := range playerList {
+		countWhitePlayer := countWhitePlayer(matchList, player)
+		countBlackPlayer := countBlackPlayer(matchList, player)
+		fmt.Fprintf(os.Stderr, "%s has %d games with white pieces and %d with black pieces.\n", player, countWhitePlayer, countBlackPlayer)
+	}
+}
+
+func countWhitePlayer(matchList []Match, player string) int {
+	c := 0
+	for _, match := range matchList {
+		if match.WhitePlayer == player {
+			c++
+		}
+	}
+	return c
+}
+
+func countBlackPlayer(matchList []Match, player string) int {
+	c := 0
+	for _, match := range matchList {
+		if match.BlackPlayer == player {
+			c++
+		}
+	}
+	return c
+}

players.txt

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+Alice
+Bob
+Charlie