trying_out_go/cmd/sum/sum.go

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package main
import (
"bufio"
"fmt"
"log"
"os"
"strconv"
)
func OpenFile(fileName string) (*os.File, error) {
fmt.Println("Opening", fileName)
return os.Open(fileName)
}
func CloseFile(file *os.File) {
fmt.Println("Closing file")
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err := file.Close()
if err != nil {
log.Fatal(err)
}
}
func GetFloats(fileName string) ([]float64, error) {
var numbers []float64
file, err := OpenFile(fileName)
if err != nil {
return nil, err
}
defer CloseFile(file)
scanner := bufio.NewScanner(file)
for scanner.Scan() {
number, err := strconv.ParseFloat(scanner.Text(), 64)
if err != nil {
return nil, err
}
numbers = append(numbers, number)
}
if scanner.Err() != nil {
return nil, scanner.Err()
}
return numbers, nil
}
func main() {
numbers, err := GetFloats(os.Args[1])
if err != nil {
log.Fatal(err)
}
var sum float64 = 0
for _, number := range numbers {
sum += number
}
fmt.Printf("Sum: %0.2f\n", sum)
}