day1, part1

day1/day-one.go

@@ -0,0 +1,53 @@
+package dayone
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"unicode"
+)
+
+func Run() {
+	file, err := os.Open("./day1/example.txt")
+	if err != nil {
+		log.Print("error opening file")
+		return
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+
+	result := 0
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		first := getFirstDigit(line)
+		last := getLastDigit(line)
+
+		num := first * 10 + last
+		result += num
+	}
+
+	fmt.Printf(">> day 1 result is %d", result)
+}
+
+func getFirstDigit(line string) int {
+	for _, ch := range line {
+		if unicode.IsDigit(ch) {
+			return int(ch - '0')
+		}
+	}
+	return 0
+}
+
+func getLastDigit(line string) int {
+	for i := len(line) - 1; i >= 0; i-- {
+		simbols := []rune(line)
+		ch := simbols[i]
+		if unicode.IsDigit(ch) {
+			return int(ch - '0')
+		}
+	}
+	return 0
+}

day1/example.txt

@@ -0,0 +1,4 @@
+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet

main.go

@@ -1,8 +1,13 @@
 package main
 
-import "fmt"
+import (
+	"fmt"
+
+	dayone "sunshine.industries/aoc2023/day1"
+)
 
 func main() {
-     s := "yoyo"
+     s := "yoyo!"
      fmt.Printf("hello, %s\n", s)
+     dayone.Run()
 }