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// run
// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"fmt"
)
type Ordered interface {
~int | ~int8 | ~int16 | ~int32 | ~int64 |
~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
~float32 | ~float64 |
~string
}
// _List is a linked list of ordered values of type T.
type _List[T Ordered] struct {
next *_List[T]
val T
}
func (l *_List[T]) Largest() T {
var max T
for p := l; p != nil; p = p.next {
if p.val > max {
max = p.val
}
}
return max
}
type OrderedNum interface {
~int | ~int8 | ~int16 | ~int32 | ~int64 |
~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
~float32 | ~float64
}
// _ListNum is a linked _List of ordered numeric values of type T.
type _ListNum[T OrderedNum] struct {
next *_ListNum[T]
val T
}
const Clip = 5
// ClippedLargest returns the largest in the list of OrderNums, but a max of 5.
// Test use of untyped constant in an expression with a generically-typed parameter
func (l *_ListNum[T]) ClippedLargest() T {
var max T
for p := l; p != nil; p = p.next {
if p.val > max && p.val < Clip {
max = p.val
}
}
return max
}
func main() {
i3 := &_List[int]{nil, 1}
i2 := &_List[int]{i3, 3}
i1 := &_List[int]{i2, 2}
if got, want := i1.Largest(), 3; got != want {
panic(fmt.Sprintf("got %d, want %d", got, want))
}
b3 := &_List[byte]{nil, byte(1)}
b2 := &_List[byte]{b3, byte(3)}
b1 := &_List[byte]{b2, byte(2)}
if got, want := b1.Largest(), byte(3); got != want {
panic(fmt.Sprintf("got %d, want %d", got, want))
}
f3 := &_List[float64]{nil, 13.5}
f2 := &_List[float64]{f3, 1.2}
f1 := &_List[float64]{f2, 4.5}
if got, want := f1.Largest(), 13.5; got != want {
panic(fmt.Sprintf("got %f, want %f", got, want))
}
s3 := &_List[string]{nil, "dd"}
s2 := &_List[string]{s3, "aa"}
s1 := &_List[string]{s2, "bb"}
if got, want := s1.Largest(), "dd"; got != want {
panic(fmt.Sprintf("got %s, want %s", got, want))
}
j3 := &_ListNum[int]{nil, 1}
j2 := &_ListNum[int]{j3, 32}
j1 := &_ListNum[int]{j2, 2}
if got, want := j1.ClippedLargest(), 2; got != want {
panic(fmt.Sprintf("got %d, want %d", got, want))
}
g3 := &_ListNum[float64]{nil, 13.5}
g2 := &_ListNum[float64]{g3, 1.2}
g1 := &_ListNum[float64]{g2, 4.5}
if got, want := g1.ClippedLargest(), 4.5; got != want {
panic(fmt.Sprintf("got %f, want %f", got, want))
}
}
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