How to use Open method of got Package

...75	}76}77func TestPriorityTwoStreams(t *testing.T) {78	ws := defaultPriorityWriteScheduler()79	ws.OpenStream(1, OpenStreamOptions{})80	ws.OpenStream(2, OpenStreamOptions{})81	want := "1{weight:15,parent:0} 2{weight:15,parent:0}"82	if got := fmtTree(ws, fmtNodeWeightParentSkipRoot); got != want {83		t.Errorf("After open\ngot  %q\nwant %q", got, want)84	}85	// Move 1's parent to 2.86	ws.AdjustStream(1, PriorityParam{87		StreamDep: 2,88		Weight:    32,89		Exclusive: false,90	})91	want = "1{weight:32,parent:2} 2{weight:15,parent:0}"92	if got := fmtTree(ws, fmtNodeWeightParentSkipRoot); got != want {93		t.Errorf("After adjust\ngot  %q\nwant %q", got, want)94	}95	if err := checkPriorityWellFormed(ws); err != nil {96		t.Error(err)97	}98}99func TestPriorityAdjustExclusiveZero(t *testing.T) {100	// 1, 2, and 3 are all children of the 0 stream.101	// Exclusive reprioritization to any of the streams should bring102	// the rest of the streams under the reprioritized stream.103	ws := defaultPriorityWriteScheduler()104	ws.OpenStream(1, OpenStreamOptions{})105	ws.OpenStream(2, OpenStreamOptions{})106	ws.OpenStream(3, OpenStreamOptions{})107	want := "1{weight:15,parent:0} 2{weight:15,parent:0} 3{weight:15,parent:0}"108	if got := fmtTree(ws, fmtNodeWeightParentSkipRoot); got != want {109		t.Errorf("After open\ngot  %q\nwant %q", got, want)110	}111	ws.AdjustStream(2, PriorityParam{112		StreamDep: 0,113		Weight:    20,114		Exclusive: true,115	})116	want = "1{weight:15,parent:2} 2{weight:20,parent:0} 3{weight:15,parent:2}"117	if got := fmtTree(ws, fmtNodeWeightParentSkipRoot); got != want {118		t.Errorf("After adjust\ngot  %q\nwant %q", got, want)119	}120	if err := checkPriorityWellFormed(ws); err != nil {121		t.Error(err)122	}123}124func TestPriorityAdjustOwnParent(t *testing.T) {125	// Assigning a node as its own parent should have no effect.126	ws := defaultPriorityWriteScheduler()127	ws.OpenStream(1, OpenStreamOptions{})128	ws.OpenStream(2, OpenStreamOptions{})129	ws.AdjustStream(2, PriorityParam{130		StreamDep: 2,131		Weight:    20,132		Exclusive: true,133	})134	want := "1{weight:15,parent:0} 2{weight:15,parent:0}"135	if got := fmtTree(ws, fmtNodeWeightParentSkipRoot); got != want {136		t.Errorf("After adjust\ngot  %q\nwant %q", got, want)137	}138	if err := checkPriorityWellFormed(ws); err != nil {139		t.Error(err)140	}141}142func TestPriorityClosedStreams(t *testing.T) {143	ws := NewPriorityWriteScheduler(&PriorityWriteSchedulerConfig{MaxClosedNodesInTree: 2}).(*priorityWriteScheduler)144	ws.OpenStream(1, OpenStreamOptions{})145	ws.OpenStream(2, OpenStreamOptions{PusherID: 1})146	ws.OpenStream(3, OpenStreamOptions{PusherID: 2})147	ws.OpenStream(4, OpenStreamOptions{PusherID: 3})148	// Close the first three streams. We lose 1, but keep 2 and 3.149	ws.CloseStream(1)150	ws.CloseStream(2)151	ws.CloseStream(3)152	want := "2{weight:15,parent:0} 3{weight:15,parent:2} 4{weight:15,parent:3}"153	if got := fmtTree(ws, fmtNodeWeightParentSkipRoot); got != want {154		t.Errorf("After close\ngot  %q\nwant %q", got, want)155	}156	if err := checkPriorityWellFormed(ws); err != nil {157		t.Error(err)158	}159	// Adding a stream as an exclusive child of 1 gives it default160	// priorities, since 1 is gone.161	ws.OpenStream(5, OpenStreamOptions{})162	ws.AdjustStream(5, PriorityParam{StreamDep: 1, Weight: 15, Exclusive: true})163	// Adding a stream as an exclusive child of 2 should work, since 2 is not gone.164	ws.OpenStream(6, OpenStreamOptions{})165	ws.AdjustStream(6, PriorityParam{StreamDep: 2, Weight: 15, Exclusive: true})166	want = "2{weight:15,parent:0} 3{weight:15,parent:6} 4{weight:15,parent:3} 5{weight:15,parent:0} 6{weight:15,parent:2}"167	if got := fmtTree(ws, fmtNodeWeightParentSkipRoot); got != want {168		t.Errorf("After add streams\ngot  %q\nwant %q", got, want)169	}170	if err := checkPriorityWellFormed(ws); err != nil {171		t.Error(err)172	}173}174func TestPriorityClosedStreamsDisabled(t *testing.T) {175	ws := NewPriorityWriteScheduler(&PriorityWriteSchedulerConfig{}).(*priorityWriteScheduler)176	ws.OpenStream(1, OpenStreamOptions{})177	ws.OpenStream(2, OpenStreamOptions{PusherID: 1})178	ws.OpenStream(3, OpenStreamOptions{PusherID: 2})179	// Close the first two streams. We keep only 3.180	ws.CloseStream(1)181	ws.CloseStream(2)182	want := "3{weight:15,parent:0}"183	if got := fmtTree(ws, fmtNodeWeightParentSkipRoot); got != want {184		t.Errorf("After close\ngot  %q\nwant %q", got, want)185	}186	if err := checkPriorityWellFormed(ws); err != nil {187		t.Error(err)188	}189}190func TestPriorityIdleStreams(t *testing.T) {191	ws := NewPriorityWriteScheduler(&PriorityWriteSchedulerConfig{MaxIdleNodesInTree: 2}).(*priorityWriteScheduler)192	ws.AdjustStream(1, PriorityParam{StreamDep: 0, Weight: 15}) // idle193	ws.AdjustStream(2, PriorityParam{StreamDep: 0, Weight: 15}) // idle194	ws.AdjustStream(3, PriorityParam{StreamDep: 2, Weight: 20}) // idle195	ws.OpenStream(4, OpenStreamOptions{})196	ws.OpenStream(5, OpenStreamOptions{})197	ws.OpenStream(6, OpenStreamOptions{})198	ws.AdjustStream(4, PriorityParam{StreamDep: 1, Weight: 15})199	ws.AdjustStream(5, PriorityParam{StreamDep: 2, Weight: 15})200	ws.AdjustStream(6, PriorityParam{StreamDep: 3, Weight: 15})201	want := "2{weight:15,parent:0} 3{weight:20,parent:2} 4{weight:15,parent:0} 5{weight:15,parent:2} 6{weight:15,parent:3}"202	if got := fmtTree(ws, fmtNodeWeightParentSkipRoot); got != want {203		t.Errorf("After open\ngot  %q\nwant %q", got, want)204	}205	if err := checkPriorityWellFormed(ws); err != nil {206		t.Error(err)207	}208}209func TestPriorityIdleStreamsDisabled(t *testing.T) {210	ws := NewPriorityWriteScheduler(&PriorityWriteSchedulerConfig{}).(*priorityWriteScheduler)211	ws.AdjustStream(1, PriorityParam{StreamDep: 0, Weight: 15}) // idle212	ws.AdjustStream(2, PriorityParam{StreamDep: 0, Weight: 15}) // idle213	ws.AdjustStream(3, PriorityParam{StreamDep: 2, Weight: 20}) // idle214	ws.OpenStream(4, OpenStreamOptions{})215	want := "4{weight:15,parent:0}"216	if got := fmtTree(ws, fmtNodeWeightParentSkipRoot); got != want {217		t.Errorf("After open\ngot  %q\nwant %q", got, want)218	}219	if err := checkPriorityWellFormed(ws); err != nil {220		t.Error(err)221	}222}223func TestPrioritySection531NonExclusive(t *testing.T) {224	// Example from RFC 7540 Section 5.3.1.225	// A,B,C,D = 1,2,3,4226	ws := defaultPriorityWriteScheduler()227	ws.OpenStream(1, OpenStreamOptions{})228	ws.OpenStream(2, OpenStreamOptions{PusherID: 1})229	ws.OpenStream(3, OpenStreamOptions{PusherID: 1})230	ws.OpenStream(4, OpenStreamOptions{})231	ws.AdjustStream(4, PriorityParam{232		StreamDep: 1,233		Weight:    15,234		Exclusive: false,235	})236	want := "1{parent:0} 2{parent:1} 3{parent:1} 4{parent:1}"237	if got := fmtTree(ws, fmtNodeParentSkipRoot); got != want {238		t.Errorf("After adjust\ngot  %q\nwant %q", got, want)239	}240	if err := checkPriorityWellFormed(ws); err != nil {241		t.Error(err)242	}243}244func TestPrioritySection531Exclusive(t *testing.T) {245	// Example from RFC 7540 Section 5.3.1.246	// A,B,C,D = 1,2,3,4247	ws := defaultPriorityWriteScheduler()248	ws.OpenStream(1, OpenStreamOptions{})249	ws.OpenStream(2, OpenStreamOptions{PusherID: 1})250	ws.OpenStream(3, OpenStreamOptions{PusherID: 1})251	ws.OpenStream(4, OpenStreamOptions{})252	ws.AdjustStream(4, PriorityParam{253		StreamDep: 1,254		Weight:    15,255		Exclusive: true,256	})257	want := "1{parent:0} 2{parent:4} 3{parent:4} 4{parent:1}"258	if got := fmtTree(ws, fmtNodeParentSkipRoot); got != want {259		t.Errorf("After adjust\ngot  %q\nwant %q", got, want)260	}261	if err := checkPriorityWellFormed(ws); err != nil {262		t.Error(err)263	}264}265func makeSection533Tree() *priorityWriteScheduler {266	// Initial tree from RFC 7540 Section 5.3.3.267	// A,B,C,D,E,F = 1,2,3,4,5,6268	ws := defaultPriorityWriteScheduler()269	ws.OpenStream(1, OpenStreamOptions{})270	ws.OpenStream(2, OpenStreamOptions{PusherID: 1})271	ws.OpenStream(3, OpenStreamOptions{PusherID: 1})272	ws.OpenStream(4, OpenStreamOptions{PusherID: 3})273	ws.OpenStream(5, OpenStreamOptions{PusherID: 3})274	ws.OpenStream(6, OpenStreamOptions{PusherID: 4})275	return ws276}277func TestPrioritySection533NonExclusive(t *testing.T) {278	// Example from RFC 7540 Section 5.3.3.279	// A,B,C,D,E,F = 1,2,3,4,5,6280	ws := defaultPriorityWriteScheduler()281	ws.OpenStream(1, OpenStreamOptions{})282	ws.OpenStream(2, OpenStreamOptions{PusherID: 1})283	ws.OpenStream(3, OpenStreamOptions{PusherID: 1})284	ws.OpenStream(4, OpenStreamOptions{PusherID: 3})285	ws.OpenStream(5, OpenStreamOptions{PusherID: 3})286	ws.OpenStream(6, OpenStreamOptions{PusherID: 4})287	ws.AdjustStream(1, PriorityParam{288		StreamDep: 4,289		Weight:    15,290		Exclusive: false,291	})292	want := "1{parent:4} 2{parent:1} 3{parent:1} 4{parent:0} 5{parent:3} 6{parent:4}"293	if got := fmtTree(ws, fmtNodeParentSkipRoot); got != want {294		t.Errorf("After adjust\ngot  %q\nwant %q", got, want)295	}296	if err := checkPriorityWellFormed(ws); err != nil {297		t.Error(err)298	}299}300func TestPrioritySection533Exclusive(t *testing.T) {301	// Example from RFC 7540 Section 5.3.3.302	// A,B,C,D,E,F = 1,2,3,4,5,6303	ws := defaultPriorityWriteScheduler()304	ws.OpenStream(1, OpenStreamOptions{})305	ws.OpenStream(2, OpenStreamOptions{PusherID: 1})306	ws.OpenStream(3, OpenStreamOptions{PusherID: 1})307	ws.OpenStream(4, OpenStreamOptions{PusherID: 3})308	ws.OpenStream(5, OpenStreamOptions{PusherID: 3})309	ws.OpenStream(6, OpenStreamOptions{PusherID: 4})310	ws.AdjustStream(1, PriorityParam{311		StreamDep: 4,312		Weight:    15,313		Exclusive: true,314	})315	want := "1{parent:4} 2{parent:1} 3{parent:1} 4{parent:0} 5{parent:3} 6{parent:1}"316	if got := fmtTree(ws, fmtNodeParentSkipRoot); got != want {317		t.Errorf("After adjust\ngot  %q\nwant %q", got, want)318	}319	if err := checkPriorityWellFormed(ws); err != nil {320		t.Error(err)321	}322}323func checkPopAll(ws WriteScheduler, order []uint32) error {324	for k, id := range order {325		wr, ok := ws.Pop()326		if !ok {327			return fmt.Errorf("Pop[%d]: got ok=false, want %d (order=%v)", k, id, order)328		}329		if got := wr.StreamID(); got != id {330			return fmt.Errorf("Pop[%d]: got %v, want %d (order=%v)", k, got, id, order)331		}332	}333	wr, ok := ws.Pop()334	if ok {335		return fmt.Errorf("Pop[%d]: got %v, want ok=false (order=%v)", len(order), wr.StreamID(), order)336	}337	return nil338}339func TestPriorityPopFrom533Tree(t *testing.T) {340	ws := makeSection533Tree()341	ws.Push(makeWriteHeadersRequest(3 /*C*/))342	ws.Push(makeWriteNonStreamRequest())343	ws.Push(makeWriteHeadersRequest(5 /*E*/))344	ws.Push(makeWriteHeadersRequest(1 /*A*/))345	t.Log("tree:", fmtTree(ws, fmtNodeParentSkipRoot))346	if err := checkPopAll(ws, []uint32{0 /*NonStream*/, 1, 3, 5}); err != nil {347		t.Error(err)348	}349}350func TestPriorityPopFromLinearTree(t *testing.T) {351	ws := defaultPriorityWriteScheduler()352	ws.OpenStream(1, OpenStreamOptions{})353	ws.OpenStream(2, OpenStreamOptions{PusherID: 1})354	ws.OpenStream(3, OpenStreamOptions{PusherID: 2})355	ws.OpenStream(4, OpenStreamOptions{PusherID: 3})356	ws.Push(makeWriteHeadersRequest(3))357	ws.Push(makeWriteHeadersRequest(4))358	ws.Push(makeWriteHeadersRequest(1))359	ws.Push(makeWriteHeadersRequest(2))360	ws.Push(makeWriteNonStreamRequest())361	ws.Push(makeWriteNonStreamRequest())362	t.Log("tree:", fmtTree(ws, fmtNodeParentSkipRoot))363	if err := checkPopAll(ws, []uint32{0, 0 /*NonStreams*/, 1, 2, 3, 4}); err != nil {364		t.Error(err)365	}366}367func TestPriorityFlowControl(t *testing.T) {368	ws := NewPriorityWriteScheduler(&PriorityWriteSchedulerConfig{ThrottleOutOfOrderWrites: false})369	ws.OpenStream(1, OpenStreamOptions{})370	ws.OpenStream(2, OpenStreamOptions{PusherID: 1})371	sc := &serverConn{maxFrameSize: 16}372	st1 := &stream{id: 1, sc: sc}373	st2 := &stream{id: 2, sc: sc}374	ws.Push(FrameWriteRequest{&writeData{1, make([]byte, 16), false}, st1, nil})375	ws.Push(FrameWriteRequest{&writeData{2, make([]byte, 16), false}, st2, nil})376	ws.AdjustStream(2, PriorityParam{StreamDep: 1})377	// No flow-control bytes available.378	if wr, ok := ws.Pop(); ok {379		t.Fatalf("Pop(limited by flow control)=%v,true, want false", wr)380	}381	// Add enough flow-control bytes to write st2 in two Pop calls.382	// Should write data from st2 even though it's lower priority than st1.383	for i := 1; i <= 2; i++ {384		st2.flow.add(8)385		wr, ok := ws.Pop()386		if !ok {387			t.Fatalf("Pop(%d)=false, want true", i)388		}389		if got, want := wr.DataSize(), 8; got != want {390			t.Fatalf("Pop(%d)=%d bytes, want %d bytes", i, got, want)391		}392	}393}394func TestPriorityThrottleOutOfOrderWrites(t *testing.T) {395	ws := NewPriorityWriteScheduler(&PriorityWriteSchedulerConfig{ThrottleOutOfOrderWrites: true})396	ws.OpenStream(1, OpenStreamOptions{})397	ws.OpenStream(2, OpenStreamOptions{PusherID: 1})398	sc := &serverConn{maxFrameSize: 4096}399	st1 := &stream{id: 1, sc: sc}400	st2 := &stream{id: 2, sc: sc}401	st1.flow.add(4096)402	st2.flow.add(4096)403	ws.Push(FrameWriteRequest{&writeData{2, make([]byte, 4096), false}, st2, nil})404	ws.AdjustStream(2, PriorityParam{StreamDep: 1})405	// We have enough flow-control bytes to write st2 in a single Pop call.406	// However, due to out-of-order write throttling, the first call should407	// only write 1KB.408	wr, ok := ws.Pop()409	if !ok {410		t.Fatalf("Pop(st2.first)=false, want true")411	}412	if got, want := wr.StreamID(), uint32(2); got != want {413		t.Fatalf("Pop(st2.first)=stream %d, want stream %d", got, want)414	}415	if got, want := wr.DataSize(), 1024; got != want {416		t.Fatalf("Pop(st2.first)=%d bytes, want %d bytes", got, want)417	}418	// Now add data on st1. This should take precedence.419	ws.Push(FrameWriteRequest{&writeData{1, make([]byte, 4096), false}, st1, nil})420	wr, ok = ws.Pop()421	if !ok {422		t.Fatalf("Pop(st1)=false, want true")423	}424	if got, want := wr.StreamID(), uint32(1); got != want {425		t.Fatalf("Pop(st1)=stream %d, want stream %d", got, want)426	}427	if got, want := wr.DataSize(), 4096; got != want {428		t.Fatalf("Pop(st1)=%d bytes, want %d bytes", got, want)429	}430	// Should go back to writing 1KB from st2.431	wr, ok = ws.Pop()432	if !ok {433		t.Fatalf("Pop(st2.last)=false, want true")434	}435	if got, want := wr.StreamID(), uint32(2); got != want {436		t.Fatalf("Pop(st2.last)=stream %d, want stream %d", got, want)437	}438	if got, want := wr.DataSize(), 1024; got != want {439		t.Fatalf("Pop(st2.last)=%d bytes, want %d bytes", got, want)440	}441}442func TestPriorityWeights(t *testing.T) {443	ws := defaultPriorityWriteScheduler()444	ws.OpenStream(1, OpenStreamOptions{})445	ws.OpenStream(2, OpenStreamOptions{})446	sc := &serverConn{maxFrameSize: 8}447	st1 := &stream{id: 1, sc: sc}448	st2 := &stream{id: 2, sc: sc}449	st1.flow.add(40)450	st2.flow.add(40)451	ws.Push(FrameWriteRequest{&writeData{1, make([]byte, 40), false}, st1, nil})452	ws.Push(FrameWriteRequest{&writeData{2, make([]byte, 40), false}, st2, nil})453	ws.AdjustStream(1, PriorityParam{StreamDep: 0, Weight: 34})454	ws.AdjustStream(2, PriorityParam{StreamDep: 0, Weight: 9})455	// st1 gets 3.5x the bandwidth of st2 (3.5 = (34+1)/(9+1)).456	// The maximum frame size is 8 bytes. The write sequence should be:457	//   st1, total bytes so far is (st1=8,  st=0)458	//   st2, total bytes so far is (st1=8,  st=8)459	//   st1, total bytes so far is (st1=16, st=8)460	//   st1, total bytes so far is (st1=24, st=8)   // 3x bandwidth461	//   st1, total bytes so far is (st1=32, st=8)   // 4x bandwidth462	//   st2, total bytes so far is (st1=32, st=16)  // 2x bandwidth463	//   st1, total bytes so far is (st1=40, st=16)464	//   st2, total bytes so far is (st1=40, st=24)465	//   st2, total bytes so far is (st1=40, st=32)466	//   st2, total bytes so far is (st1=40, st=40)467	if err := checkPopAll(ws, []uint32{1, 2, 1, 1, 1, 2, 1, 2, 2, 2}); err != nil {468		t.Error(err)469	}470}471func TestPriorityRstStreamOnNonOpenStreams(t *testing.T) {472	ws := NewPriorityWriteScheduler(&PriorityWriteSchedulerConfig{473		MaxClosedNodesInTree: 0,474		MaxIdleNodesInTree:   0,475	})476	ws.OpenStream(1, OpenStreamOptions{})477	ws.CloseStream(1)478	ws.Push(FrameWriteRequest{write: streamError(1, ErrCodeProtocol)})479	ws.Push(FrameWriteRequest{write: streamError(2, ErrCodeProtocol)})480	if err := checkPopAll(ws, []uint32{1, 2}); err != nil {481		t.Error(err)482	}483}...

1import "fmt"2func main() {3    f, err := os.Open("test.txt")4    if err != nil {5        fmt.Println(err)6    }7    defer f.Close()8    bs := make([]byte, 1024)9    for {10        n1, err := f.Read(bs)11        if err != nil && err != io.EOF {12            fmt.Println(err)13        }14        if n1 == 0 {15        }16        fmt.Print(string(bs[:n1]))17    }18}19import "fmt"20func main() {21    bs, err := ioutil.ReadFile("test.txt")22    if err != nil {23    }24    str := string(bs)25    fmt.Println(str)26}27import "fmt"28func main() {29    fileInfos, err := ioutil.ReadDir("C:/Users/YourName/Desktop")30    if err != nil {31    }32    for _, fi := range fileInfos {33        fmt.Println(fi.Name())34    }35}36import "fmt"37func main() {38    bs := []byte(str)39    err := ioutil.WriteFile("test.txt", bs, 0644)40    if err != nil {41    }42}43import "fmt"44func main() {45    f, err := os.Create("test.txt")46    if err != nil {47    }48    defer f.Close()49    f.WriteString("Hello World")50}51import "fmt"52func main() {53    f, err := os.Create("test.txt")54    if err != nil {55    }56    defer f.Close()57    f.Write([]byte("Hello World"))58}59import "fmt"60func main() {61    f, err := os.Create("test.txt")

1import (2func main() {3    fi, err := os.Open("test.txt")4    if err != nil {5        fmt.Println("Error: The file doesn't exist")6    }7    defer func() {8        if err := fi.Close(); err != nil {9            panic(err)10        }11    }()12    r := bufio.NewReader(fi)13    line, err := r.ReadString('14    if err != nil {15        fmt.Println("Error: Couldn't read the file.")16    }17    fmt.Print(line)18}

1import "os"2func main() {3file, err := os.Open("1.txt")4if err != nil {5fmt.Println(err)6}7defer file.Close()8}9import "os"10func main() {11file, err := os.OpenFile("1.txt", os.O_RDWR, 0644)12if err != nil {13fmt.Println(err)14}15defer file.Close()16}17import "os"18func main() {19file, err := os.Create("1.txt")20if err != nil {21fmt.Println(err)22}23defer file.Close()24}25import "os"26func main() {27file, err := os.NewFile(1, "1.txt")28if err != nil {29fmt.Println(err)30}31defer file.Close()32}33import "os"34func main() {35err := os.Mkdir("1.txt", 0755)36if err != nil {37fmt.Println(err)38}39}40import "os"41func main() {42err := os.MkdirAll("1.txt", 0755)43if err != nil {44fmt.Println(err)45}46}47import "os"48func main() {49err := os.Remove("1.txt")50if err != nil {51fmt.Println(err)52}53}54import "os"55func main() {56err := os.RemoveAll("1.txt")57if err != nil {58fmt.Println(err)59}60}61import "os"62func main() {63err := os.Rename("1.txt", "2.txt")64if err != nil {65fmt.Println(err)66}67}

1import (2func main() {3    s.Open()4}5import (6func main() {7    s.Open()8}9import (10type got struct {11}12func (g *got) Open() {13    fmt.Println("open")14}15func (g *got) Close() {16    fmt.Println("close")17}

1import (2func main() {3fmt.Println("Hello, playground")4data, err := ioutil.ReadFile("1.txt")5if err != nil {6fmt.Println("File reading error", err)7}8fmt.Println("Contents of file:", string(data))9}10import (11func main() {12fmt.Println("Hello, playground")13data, err := ioutil.ReadFile("2.txt")14if err != nil {15fmt.Println("File reading error", err)16}17fmt.Println("Contents of file:", string(data))18}19import (20func main() {21fmt.Println("Hello, playground")22data, err := ioutil.ReadFile("3.txt")23if err != nil {24fmt.Println("File reading error", err)25}26fmt.Println("Contents of file:", string(data))27}28import (29func main() {30fmt.Println("Hello, playground")31data, err := ioutil.ReadFile("4.txt")32if err != nil {33fmt.Println("File reading error", err)34}35fmt.Println("Contents of file:", string(data))36}37import (38func main() {39fmt.Println("Hello, playground")40data, err := ioutil.ReadFile("5.txt")41if err != nil {42fmt.Println("File reading error", err)43}44fmt.Println("Contents of file:", string(data))45}46import (47func main() {48fmt.Println("Hello, playground")49data, err := ioutil.ReadFile("6.txt")50if err != nil {51fmt.Println("File reading error", err)52}53fmt.Println("Contents of file:", string(data))54}55import (56func main() {57fmt.Println("Hello, playground")58data, err := ioutil.ReadFile("7.txt")