103 lines
2.0 KiB
Go
103 lines
2.0 KiB
Go
package main
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import (
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"bufio"
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"fmt"
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"os"
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"strconv"
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"strings"
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)
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func main() {
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directory, err := os.Getwd()
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Error(err)
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fmt.Printf("What is the name of the file: ")
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reader := bufio.NewReader(os.Stdin)
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input, err := reader.ReadString('\n')
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Error(err)
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input = strings.TrimSpace(input)
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file, err := os.Open(input)
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Error(err)
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var upcs []string
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scanner := bufio.NewScanner(file)
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for scanner.Scan() {
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upcs = append(upcs, scanner.Text())
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}
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err = file.Close()
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Error(err)
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if scanner.Err() != nil {
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fmt.Println(scanner.Err())
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}
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var gtins []string
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for _, upc := range upcs {
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upcLength := len(upc)
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// Check Digit Formula
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// Take all the digits in odd positions, add them and multiply by three
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// Take all the digits in even positions (except for the last one) and add to the number you got above
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// Divide that number by 10 and take the remainder
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// If the remainder is not 0, subtract it from 10
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oddNumber := 0
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evenNumber := 0
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var remainder int
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if upcLength < 10 {
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gtins = append(gtins, "Cannot process upcs less than 10 digits")
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continue
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}
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if upcLength == 10 {
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upc = "0" + upc
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}
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if upcLength > 13 {
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gtins = append(gtins, "GTINs longer than 14 digits are not valid")
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}
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for i, num := range upc {
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if i%2 == 0 {
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oddString, err := strconv.Atoi(string(num))
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Error(err)
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oddNumber += oddString
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} else {
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if upcLength-1 > i {
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evenString, err := strconv.Atoi(string(num))
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Error(err)
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evenNumber += evenString
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}
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}
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}
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oddNumber = oddNumber * 3
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remainder = (oddNumber + evenNumber) % 10
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if remainder != 0 {
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remainder = 10 - remainder
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}
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remainderString := strconv.Itoa(remainder)
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gtins = append(gtins, upc+remainderString)
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}
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if _, err := os.Stat(directory + "/answer.txt"); err == nil {
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e := os.Remove(directory + "/answer.txt")
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Error(e)
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}
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answerFile, err := os.Create(directory + "/answer.txt")
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Error(err)
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defer answerFile.Close()
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for _, gtin := range gtins {
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_, err := answerFile.WriteString(gtin + "\n")
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Error(err)
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}
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}
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