update solutions.pdf, compact the TODOs

README.md

@@ -189,7 +189,7 @@ List of exercises and examples (x)
 * [S08](https://github.com/miku/exploreio/tree/master/s08): Strings can be readers, io.ReadFull.
 * [S09](https://github.com/miku/exploreio/tree/master/s09): Random reader and Base64 encoder.
 * [S10](https://github.com/miku/exploreio/tree/master/s10): Prettify tabular data.
-* [S11](https://github.com/miku/exploreio/tree/master/s11): Read a file, line by line.
+* [S11](https://github.com/miku/exploreio/tree/master/s11): Read a file, line by line. (x)
 * [S12](https://github.com/miku/exploreio/tree/master/s12): Read from multiple readers in turn.
 * [S13](https://github.com/miku/exploreio/tree/master/s13): Write to more than one writer at once.
 * [S14](https://github.com/miku/exploreio/tree/master/s14): Read into variables.

s00/main.go

@@ -23,7 +23,8 @@ import (
  "os"
 )
 
-// TODO: Change a single character in this program so the complete file is read and printed.
+// TODO: Change a single character in this program so the complete
+// file is read and printed.
 func main() {
  file, err := os.Open("hello.txt")
  if err != nil {

s01/main.go

@@ -21,8 +21,9 @@ func main() {
  log.Fatal(err)
  }
 
- // TODO: We don't need to loop manually, there is a helper function for that.
- // TODO: Replace the next 10 lines with 5 that do the same.
+ // TODO: We don't need to loop manually, there is a helper
+ // function for that. Replace the next 10 lines
+ // with 5 lines that do the same.
  var contents []byte
  for {
  b := make([]byte, 8)

s02/main.go

@@ -19,7 +19,8 @@ func main() {
  log.Fatal(err)
  }
 
- // TODO: Write contents of the file to the standard output, without using a byte slice (3 lines).
+ // TODO: Write contents of the file to the standard output,
+ // without using a byte slice (3 lines).
  // ...
  // ...
  // ...

s03/main.go

@@ -10,7 +10,7 @@ package main
 
 func main() {
  // TODO: Read input from standard input and pass it to standard output,
- // TODO: without using a byte slice (3 lines).
+ //   without using a byte slice (3 lines).
  // ...
  // ...
  // ...

s04/main.go

@@ -7,8 +7,10 @@
 package main
 
 func main() {
- // TODO: Read gzip compressed input from standard input and print it to standard output,
- // TODO: without using a byte slice (7 lines).
+
+ // TODO: Read gzip compressed data from standard input and write
+ // to standard output, without using a byte slice (7 lines).
+ //
  // ...
  // ...
  // ...

s05/main.go

@@ -13,9 +13,7 @@
 package main
 
 import (
- "image"
  _ "image/gif" // register gif decoder
- "image/jpeg"
  _ "image/png" // register png decoder
  "io"
  "log"
@@ -24,8 +22,10 @@ import (
 
 // toJPG converts a GIF or PNG image int JPEG.
 func toJPG(r io.Reader, w io.Writer) error {
- // TODO: Decode the image and encode it to JPEG, write it to the given writer (5 lines).
- // TODO: Hint: Utilize methods taking io.Reader or io.Writer in https://golang.org/pkg/image/.
+ // TODO: Decode the image and encode it to JPEG, write it
+ // to the given writer (5 lines).
+ // Hint: Utilize methods taking io.Reader or io.Writer
+ // in https://golang.org/pkg/image/.
  // ...
  // ...
  // ...

s08/main.go

@@ -9,12 +9,14 @@ package main
 import (
  "fmt"
  "io"
+ "log"
  "strings"
 )
 
 func main() {
  r := strings.NewReader(`Strings can be readers, too.`)
- // TODO: Read the first 7 bytes of the string into a byte slice, then print to stdout (5 lines).
+ // TODO: Read the first 7 bytes of the string into a byte slice,
+ // then print to stdout (5 lines).
  b := make([]byte, 7)
  if _, err := io.ReadFull(r, b); err != nil {
  log.Fatal(err)

s10/main.go

@@ -11,8 +11,6 @@
 package main
 
 import (
- "io"
- "log"
  "os"
  "text/tabwriter"
 )
@@ -21,7 +19,8 @@ func main() {
  // https://golang.org/pkg/text/tabwriter/#NewWriter
  w := tabwriter.NewWriter(os.Stdout, 0, 0, 1, ' ', tabwriter.AlignRight|tabwriter.Debug)
 
- // TODO: Read tabulated data from standard in and write it to the tabwriter (3 lines).
+ // TODO: Read tabulated data from standard in
+ // and write it to the tabwriter (3 lines).
  // ...
  // ...
  // ...

s12/main.go

@@ -11,13 +11,12 @@ package main
 
 import (
  "io"
- "log"
- "os"
  "strings"
 )
 
 func main() {
- // TODO: Read from these four readers and write to standard output (4 lines).
+ // TODO: Read from these four readers
+ // and write to standard output (4 lines).
  rs := []io.Reader{
  strings.NewReader("Hello\n"),
  strings.NewReader("Gopher\n"),

s14/main.go

@@ -18,7 +18,8 @@ func main() {
  f float64
  s string
  )
- // TODO: Read an int, a float and a string from standard input (3 lines).
+ // TODO: Read an int, a float and a string from
+ // standard input (3 lines).
  // ...
  // ...
  // ...

s15/main.go

@@ -19,18 +19,16 @@ package main
 
 import (
  "bytes"
- "fmt"
- "io"
  "log"
- "os"
 )
 
 func main() {
  var buf bytes.Buffer
  if _, err := buf.WriteString("abc.xyz"); err != nil {
  log.Fatal(err)
  }
- // TODO: Read one byte at a time from the buffer and print the hex value on stdout (10 lines).
+ // TODO: Read one byte at a time from the buffer
+ // and print the hex value on stdout (10 lines).
  // ...
  // ...
  // ...

s18b/main.go

@@ -20,10 +20,8 @@
 package main
 
 import (
- "io"
  "log"
  "net"
- "os"
 )
 
 func main() {
@@ -32,5 +30,6 @@ func main() {
  log.Fatal(err)
  }
  defer conn.Close()
- // TODO: Send a GET request, read the reponse and print it to standard output (6 lines).
+ // TODO: Send a GET request, read the reponse and print it
+ // to standard output (6 lines).
 }

s21/main.go

@@ -5,7 +5,6 @@
 package main
 
 import (
- "bytes"
  "io"
  "log"
  "os"
@@ -16,7 +15,8 @@ type UpperReader struct {
  r io.Reader
 }
 
-// TODO: Implement UpperReader, a reader that converts all Unicode letter mapped to their upper case (6 lines).
+// TODO: Implement UpperReader, a reader that converts
+// all Unicode letter mapped to their upper case (6 lines).
 func (r *UpperReader) Read(p []byte) (n int, err error) {
  // ...
  // ...

s22/main.go

@@ -12,7 +12,8 @@ import (
  "os"
 )
 
-// TODO: Implement type Discard, which throws away everything that is written to it (4 lines).
+// TODO: Implement type Discard, which throws away
+// everything that is written to it (4 lines).
 // ...
 
 // ...

s23/main.go

@@ -12,7 +12,8 @@ import (
  "os"
 )
 
-// TODO: Implement UpperWriter, a reader that converts all Unicode letter mapped to their upper case (6 lines).
+// TODO: Implement UpperWriter, a reader that converts
+// all Unicode letter mapped to their upper case (6 lines).
 // ...
 // ...
 // ...

s24a/main.go

@@ -12,11 +12,13 @@ import (
  "io/ioutil"
  "log"
  "os"
- "sync/atomic"
 )
 
-// TODO: Implement a reader that counts the total number of bytes read (12 lines).
-// TODO: It should have a Count() uint64 method, that returns the number of bytes read so far.
+// TODO: Implement a reader that counts the total
+// number of bytes read.
+// It should have a Count() uint64 method,
+// that returns the number of bytes read so far.
+// (12 lines).
 // ...
 // ...
 // ...

s27b/main.go

@@ -27,7 +27,8 @@ type TimeoutReader struct {
  timeout time.Duration
 }
 
-// TODO: Implement a reader that times out after a certain a given timeout (21 lines).
+// TODO: Implement a reader that times out after
+// a certain a given timeout (21 lines).
 // ...
 // ...
 // ...

s41/main.go

@@ -1,4 +1,4 @@
-// Can we read concurrently from a reader?
+// S41: Can we read concurrently from a reader?
 //
 // $ go run main.go | head -10
 // 0

s43/main.go

@@ -1,4 +1,4 @@
-// S43: Like /dev/zero
+// S43: Like /dev/zero.
 //
 // OUTPUT:
 //