108 строки
1,7 КиБ
Go
108 строки
1,7 КиБ
Go
package main
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type Thing struct {
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name string
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}
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func (t Thing) String() string {
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return t.name
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}
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type Stringer interface {
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String() string
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}
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const SIX = 6
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func main() {
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println("Hello world from Go!")
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println("The answer is:", calculateAnswer())
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println("5 ** 2 =", square(5))
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println("3 + 12 =", add(3, 12))
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println("fib(11) =", fib(11))
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println("sumrange(100) =", sumrange(100))
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println("strlen foo:", strlen("foo"))
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foo := []int{1, 2, 4, 5}
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println("len/cap foo:", len(foo), cap(foo))
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println("foo[3]:", foo[3])
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println("sum foo:", sum(foo))
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thing := &Thing{"foo"}
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println("thing:", thing.String())
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printItf(5)
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printItf(byte('x'))
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printItf("foo")
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printItf(*thing)
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printItf(thing)
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printItf(Stringer(thing))
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s := Stringer(thing)
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println("Stringer.String():", s.String())
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runFunc(hello, 5) // must be indirect to avoid obvious inlining
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}
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func runFunc(f func(int), arg int) {
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f(arg)
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}
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func hello(n int) {
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println("hello from function pointer:", n)
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}
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func strlen(s string) int {
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return len(s)
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}
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func printItf(val interface{}) {
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switch val := val.(type) {
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case int:
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println("is int:", val)
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case byte:
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println("is byte:", val)
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case string:
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println("is string:", val)
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case Thing:
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println("is Thing:", val.String())
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case *Thing:
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println("is *Thing:", val.String())
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default:
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println("is ?")
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}
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}
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func calculateAnswer() int {
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seven := 7
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return SIX * seven
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}
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func square(n int) int {
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return n * n
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}
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func add(a, b int) int {
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return a + b
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}
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func fib(n int) int {
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if n <= 2 {
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return 1
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}
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return fib(n-1) + fib(n-2)
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}
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func sumrange(n int) int {
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sum := 0
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for i := 1; i <= n; i++ {
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sum += i
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}
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return sum
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}
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func sum(l []int) int {
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sum := 0
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for _, n := range l {
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sum += n
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}
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return sum
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}
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