Implement concurrent CSV processing with goroutines

cur/dan/main.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"encoding/csv"
+	"fmt"
+	"os"
+	"strconv"
+	"sync"
+	"time"
+)
+
+// parseRow is the worker function that processes one CSV row
+func parseRow(row string, ch chan<- float64, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	// Simulate real work with delay
+	time.Sleep(500 * time.Millisecond)
+
+	// Parse the CSV row manually (split by comma)
+	var cost float64
+	lastCommaIdx := -1
+	for i := len(row) - 1; i >= 0; i-- {
+		if row[i] == ',' {
+			lastCommaIdx = i
+			break
+		}
+	}
+
+	if lastCommaIdx != -1 {
+		costStr := row[lastCommaIdx+1:]
+		parsedCost, err := strconv.ParseFloat(costStr, 64)
+		if err == nil {
+			cost = parsedCost
+		}
+	}
+
+	// Send the cost to the channel
+	ch <- cost
+}
+
+func main() {
+	startTime := time.Now()
+
+	// Read the CSV file
+	file, err := os.Open("../testcur.csv")
+	if err != nil {
+		fmt.Println("Error opening file:", err)
+		return
+	}
+	defer file.Close()
+
+	reader := csv.NewReader(file)
+	records, err := reader.ReadAll()
+	if err != nil {
+		fmt.Println("Error reading CSV:", err)
+		return
+	}
+
+	// Skip header row
+	if len(records) > 0 {
+		records = records[1:]
+	}
+
+	// Create channel and WaitGroup
+	costChannel := make(chan float64, len(records))
+	var wg sync.WaitGroup
+
+	// Launch a goroutine for each row
+	for _, record := range records {
+		// Convert record back to string format for parseRow
+		rowStr := record[0] + "," + record[1] + "," + record[2]
+		wg.Add(1)
+		go parseRow(rowStr, costChannel, &wg)
+	}
+
+	// Wait for all workers to finish, then close the channel
+	go func() {
+		wg.Wait()
+		close(costChannel)
+	}()
+
+	// Collect all costs from the channel
+	var totalCost float64
+	var rowsProcessed int
+	for cost := range costChannel {
+		totalCost += cost
+		rowsProcessed++
+	}
+
+	// Calculate elapsed time
+	elapsed := time.Since(startTime)
+
+	// Print results
+	fmt.Printf("Total Cost: $%.2f\n", totalCost)
+	fmt.Printf("Rows Processed: %d\n", rowsProcessed)
+	fmt.Printf("Total Time Taken: %v\n", elapsed)
+}