Golangで探る！ジェネリクス活用の実践テクニック

package main

import "fmt"

func Reduce[T any](s []T, init T, f func(T, T) T) T {
    acc := init
    for _, v := range s {
        acc = f(acc, v)
    }
    return acc
}

func main() {
    ints := []int{1, 2, 3, 4, 5}
    sum := Reduce(ints, 0, func(a, b int) int { return a + b })
    fmt.Println("Sum:", sum)
}

package main

import "fmt"

type Stack[T any] struct {
    elements []T
}

func (s *Stack[T]) Push(v T) {
    s.elements = append(s.elements, v)
}

func (s *Stack[T]) Pop() T {
    if len(s.elements) == 0 {
        panic("stack is empty")
    }
    v := s.elements[len(s.elements)-1]
    s.elements = s.elements[:len(s.elements)-1]
    return v
}

func main() {
    stack := Stack[int]{}
    stack.Push(42)
    stack.Push(23)
    fmt.Println("Pop:", stack.Pop())
    fmt.Println("Pop:", stack.Pop())
}