update: log parser dir to input scanning

23-input-scanning/03-project-log-parser/log.txt

@@ -0,0 +1,6 @@
+learngoprogramming.com 10
+learngoprogramming.com 10
+golang.org 4
+golang.org 6
+blog.golang.org 20
+blog.golang.org 10

23-input-scanning/03-project-log-parser/log_err_missing.txt

@@ -0,0 +1,6 @@
+learngoprogramming.com 10
+learngoprogramming.com 10
+golang.org
+golang.org 6
+blog.golang.org 20
+blog.golang.org 10

23-input-scanning/03-project-log-parser/log_err_negative.txt

@@ -0,0 +1,6 @@
+learngoprogramming.com 10
+learngoprogramming.com 10
+golang.org -100
+golang.org 6
+blog.golang.org 20
+blog.golang.org 10

23-input-scanning/03-project-log-parser/log_err_str.txt

@@ -0,0 +1,6 @@
+learngoprogramming.com 10
+learngoprogramming.com 10
+golang.org FOUR
+golang.org 6
+blog.golang.org 20
+blog.golang.org 10

23-input-scanning/03-project-log-parser/main.go

@@ -0,0 +1,78 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	var (
+		sum     map[string]int // total visits per domain
+		domains []string       // unique domain names
+		total   int            // total visits to all domains
+		lines   int            // number of parsed lines (for the error messages)
+	)
+
+	sum = make(map[string]int)
+
+	// Scan the standard-in line by line
+	in := bufio.NewScanner(os.Stdin)
+	for in.Scan() {
+		lines++
+
+		// Parse the fields
+		fields := strings.Fields(in.Text())
+		if len(fields) != 2 {
+			fmt.Printf("wrong input: %v (line #%d)\n", fields, lines)
+			return
+		}
+
+		domain := fields[0]
+
+		// Sum the total visits per domain
+		visits, err := strconv.Atoi(fields[1])
+		if visits < 0 || err != nil {
+			fmt.Printf("wrong input: %q (line #%d)\n", fields[1], lines)
+			return
+		}
+
+		// Collect the unique domains
+		if _, ok := sum[domain]; !ok {
+			domains = append(domains, domain)
+		}
+
+		// Keep track of total and per domain visits
+		total += visits
+		sum[domain] += visits
+	}
+
+	// Print the visits per domain
+	sort.Strings(domains)
+
+	fmt.Printf("%-30s %10s\n", "DOMAIN", "VISITS")
+	fmt.Println(strings.Repeat("-", 45))
+
+	for _, domain := range domains {
+		visits := sum[domain]
+		fmt.Printf("%-30s %10d\n", domain, visits)
+	}
+
+	// Print the total visits for all domains
+	fmt.Printf("\n%-30s %10d\n", "TOTAL", total)
+
+	// Let's handle the error
+	if err := in.Err(); err != nil {
+		fmt.Println("> Err:", err)
+	}
+}