//
//	1.21 < 1.21rc1 < 1.21.0
//
// meaning that Go 1.21rc1 and Go 1.21.0 will both handle go.mod files that
// say "go 1.21", but Go 1.21rc1 will not handle files that say "go 1.21.0".
func IsLang(x string) bool {
	return gover.IsLang(x)
}

// Lang returns the Go language version. For example, Lang("1.2.3") == "1.2".
func Lang(x string) string {
	return gover.Lang(x)
}

var langTests = []testCase1[string, string]{
	{"1.2rc3", "1.2"},
	{"1.2.3", "1.2"},
	{"1.2", "1.2"},
	{"1", "1"},
	{"1.999testmod", "1.999"},
}

func TestIsLang(t *testing.T) { test1(t, isLangTests, "IsLang", IsLang) }

var isLangTests = []testCase1[string, bool]{
	{"1.2rc3", false},
	{"1.2.3", false},
	{"1.999testmod", false},
	{"1.22", true},
	{"1.21", true},
	{"1.20", false}, // == 1.20.0

var langTests = []testCase1[string, string]{
	{"1.2rc3", "1.2"},
	{"1.2.3", "1.2"},
	{"1.2", "1.2"},
	{"1", "1"},
	{"1.999testmod", "1.999"},
}

func TestIsLang(t *testing.T) { test1(t, isLangTests, "IsLang", IsLang) }

var isLangTests = []testCase1[string, bool]{
	{"1.2rc3", false},
	{"1.2.3", false},
	{"1.999testmod", false},
	{"1.22", true},
	{"1.21", true},
	{"1.20", false}, // == 1.20.0

// compared using Compare.
// If x and y compare equal, Max returns x.
func Max(x, y string) string {
	if Compare(x, y) < 0 {
		return y
	}
	return x
}

// IsLang reports whether v denotes the overall Go language version
// and not a specific release. Starting with the Go 1.21 release, "1.x" denotes
// the overall language version; the first release is "1.x.0".

	// we don't need to access the network to know that it exists.
	if r.path == "toolchain" && v == gover.Local() {
		return &RevInfo{Version: prefix + v}, nil
	}

	if gover.IsLang(v) {
		// We can only use a language (development) version if the current toolchain
		// implements that version, and the two checks above have ruled that out.

				// Don't try to download a language version (sans patch component), such as go1.22.
				// Instead, use the first toolchain of that language version, such as 1.22.0.
				// See golang.org/issue/62278.
				if gover.IsLang(goVers) && gover.Compare(goVers, "1.21") >= 0 {
					gotoolchain += ".0"
				}
				gover.Startup.AutoGoVersion = goVers
				gover.Startup.AutoToolchain = "" // in case we are overriding it for being too old
			}
		}

	// checking that the toolchain is new enough for the Go version.
	toolchain := "go" + old
	if wf.Toolchain != nil {
		toolchain = wf.Toolchain.Name
	}
	if gover.IsLang(gover.Local()) {
		toolchain = gover.ToolchainMax(toolchain, "go"+goVers)
	} else {
		toolchain = gover.ToolchainMax(toolchain, "go"+gover.Local())
	}

	// Drop the toolchain line if it is implied by the go line

{!../../../docs_src/python_types/tutorial001.py!}
```

Kết quả khi gọi chương trình này:

```
John Doe
```

Hàm thực hiện như sau:

* Lấy một `first_name` và `last_name`.
* Chuyển đổi kí tự đầu tiên của mỗi biến sang kiểu chữ hoa với `title()`.
* <abbr title="Đặt chúng lại với nhau thành một. Với các nội dung lần lượt.">Nối</abbr> chúng lại với nhau bằng một kí tự trắng ở giữa.

```Python hl_lines="2"

// license that can be found in the LICENSE file.

package rand

import (
	"math"
)

/*
 * Normal distribution
 *
 * See "The Ziggurat Method for Generating Random Variables"
 * (Marsaglia & Tsang, 2000)
 * http://www.jstatsoft.org/v05/i08/paper [pdf]
 */

const (
	rn = 3.442619855899
)

func absInt32(i int32) uint32 {
	if i < 0 {
		return uint32(-i)
	}
	return uint32(i)
}

// license that can be found in the LICENSE file.

package rand

import (
	"math"
)

/*
 * Normal distribution
 *
 * See "The Ziggurat Method for Generating Random Variables"
 * (Marsaglia & Tsang, 2000)
 * http://www.jstatsoft.org/v05/i08/paper [pdf]
 */

const (
	rn = 3.442619855899
)

func absInt32(i int32) uint32 {
	if i < 0 {
		return uint32(-i)
	}
	return uint32(i)
}