Golang Learning: Read and write files (for process edition)

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package main import  ("FMT" "Bufio" "IO" "OS" "Flag" "StrConv")//  use the command line  -in  The default is Infilevar in *string = flag. String ("in",  "infile",  "input file name  ...") var out *string =  Flag. String ("Out",  "outfile",  "output file name  ...") Func main ()  {//  Parse command line flag. Parse () Defer func ()  {//  If an exception is found ... if ex := recover (); nil!=ex {fmt. Println (Ex)}} () Value, err := read () if nil != err {//  throws Exception Panic (err)} Write (value)}func write (value []int)   (err error)  {//  Create file file, err2 :=  os. Create (*out) if nil != err2 {err = err2fmt. Println ("Error to create file ...") return}//  no matter what, finally close the file defer file. Close () for _, res := range value {//  convert int type to stringstr :=  StrConv. Itoa (res+2)//  writes a string to file in file. WriteString (str +  "\ n")}return nil}func read ()   (result []int, err  Error)  {//  open file File, err1 := os. Open (*in) if nil != err1 {err = err1return}//  no matter what, finally close the file defer file. Close ()//  creates a Bufferreaderbr := bufio from the file. Newreader (file)//  Initializes an array slice result = make ([]int, 0)//  the dead loop for {//  a line of read lines,  isprefix, err2 := br. ReadLine () if nil != err2 {//  read to the end of the file If io. Eof == err2 {fmt. Println ("finish read&nbsp ...")}return}if isprefix {break}//  converts a character array to a string str :=  String//  converts the string to Intvalue, err3 := strconv. Atoi (str) if nil != err3 {err = err3break}//  in a slice like result = append (Result, value)}   Returns the result return}