Refactor parsing of digits to handle errors and convert strings to integers

day1/part2.go

@@ -1,14 +1,13 @@
 package main
 
 import (
+	"bufio"
 	"errors"
 	"fmt"
 	"io"
 	"log"
 	"os"
 	"regexp"
-	"strconv"
-	"strings"
 )
 
 func readInput() string {
@@ -21,64 +20,103 @@ func readInput() string {
 	return str
 }
 
-func parseDigit(input string) (string, error) {
-	digits := map[string]string{
-		"one":   "1",
-		"two":   "2",
-		"three": "3",
-		"four":  "4",
-		"five":  "5",
-		"six":   "6",
-		"seven": "7",
-		"eight": "8",
-		"nine":  "9",
-		"1":     "1",
-		"2":     "2",
-		"3":     "3",
-		"4":     "4",
-		"5":     "5",
-		"6":     "6",
-		"7":     "7",
-		"8":     "8",
-		"9":     "9",
+func readFile() string {
+	file, err := os.ReadFile("input.txt")
+	if err != nil {
+		panic(err)
+	}
+	str := string(file)
+	return str
+}
+
+func readFileLineByLine() []string {
+	var lines []string
+	file, err := os.Open("input.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	// optionally, resize scanner's capacity for lines over 64K, see next example
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+	return lines
+}
+
+func parseDigit(input string) (int, error) {
+	digits := map[string]int{
+		"one":   1,
+		"two":   2,
+		"three": 3,
+		"four":  4,
+		"five":  5,
+		"six":   6,
+		"seven": 7,
+		"eight": 8,
+		"nine":  9,
+		"1":     1,
+		"2":     2,
+		"3":     3,
+		"4":     4,
+		"5":     5,
+		"6":     6,
+		"7":     7,
+		"8":     8,
+		"9":     9,
 	}
 	i, ok := digits[input]
 	if ok == false {
-		return "", errors.New("No spelled digit")
+		return 0, errors.New("err")
 	}
 	return i, nil
 }
 
-func addDStrings(input1 string, input2 string) string {
-	num1, err := parseDigit(input1)
-	if err != nil {
-		num1 = input1
-	}
-	num2, err := parseDigit(input2)
-	if err != nil {
-		num2 = input2
-	}
-	num_str := num1 + num2
-	return num_str
-}
+// func addDStrings(input1 string, input2 string) string {
+// 	num1, err := parseDigit(input1)
+// 	if err != nil {
+// 		num1 = input1
+// 		log.Fatalln(err)
+// 	}
+// 	num2, err := parseDigit(input2)
+// 	if err != nil {
+// 		num2 = input2
+// 		log.Fatalln(err)
+// 	}
+// 	num_str := num1 + num2
+// 	println(num_str)
+// 	return num_str
+// }
 
 func main() {
-	lines := strings.Split(readInput(), "\n")
+	// lines := strings.Split(readFile(), "\n")
+	lines := readFileLineByLine()
 	re := regexp.MustCompile(`(one|two|three|four|five|six|seven|eight|nine|\d)`)
 	var answer int
 	for _, l := range lines {
 		matches := re.FindAllString(l, -1)
 		matches_len := len(matches)
 		if matches_len == 0 {
-			continue
+			break
 		}
 		first := matches[0]
 		last := matches[matches_len-1]
-		num_str := addDStrings(first, last)
-		num, err := strconv.Atoi(num_str)
+		num_f, err := parseDigit(first)
 		if err != nil {
 			log.Fatalln(err)
 		}
+		num_l, err := parseDigit(last)
+		// num_str := addDStrings(first, last)
+		// num, err := strconv.Atoi(num_str)
+		if err != nil {
+			log.Fatalln(err)
+		}
+		num := (num_f * 10) + num_l
 		answer = answer + num
 		fmt.Println(l, first, last, num)
 	}