package main
import (
"fmt"
"os"
"bufio"
)
func IterLinesInFile(filePath string, process func (s string) bool) error {
file, err := os.Open(filePath)
if err != nil {
return err
}
defer file.Close()
scanner := bufio.NewScanner(file)
// Scan() reads next line and returns false when reached end or error
for scanner.Scan() {
line := scanner.Text()
if !process(line) {
return nil
}
// process the line
}
// check if Scan() finished because of error or because it reached end of file
return scanner.Err()
}
func main() {
nLines := 0
IterLinesInFile("main.go", func(s string) bool {
nLines++
return true
})
fmt.Printf("%d lines in 'main.go'\n", nLines)
}
