英文:
Why counter not increase on function argument via method
问题
我尝试编写一个简单的计数器，但我不明白为什么它不起作用。这是我的代码：
package mainimport "fmt"type Count inttype Counter interface {Next()Prev()Jump(j int) //我想将Count增加到'j'的值}func (c *Count) Next() { *c += 1 }func (c *Count) Prev() { *c -= 1 }func (c *Count) Jump(j int) { *c += j } //这里有错误func main() {val := new(Count) //0val.Next() //+1val.Jump(4) //+4val.Prev() //-1fmt.Println("现在是", *val) //期望输出4}
有人知道这里的问题吗？提前感谢！
英文:
I try writing simple counter but I don't understand why he didn't work.. There is my code
package mainimport "fmt"type Count inttype Counter interface {Next()Prev()Jump(j int) //i want increase Count to 'j' value}func (c *Count) Next() { *c += 1 }func (c *Count) Prev() { *c -= 1 }func (c *Count) Jump(j int) { *c += j } //Here Errorfunc main() {val := new(Count) //0val.Next() //+1val.Jump(4) //+4val.Prev() //-1fmt.Println("Now ", *val) //expected 4}
Is anybody knows what the problem here?
Thanks for advance!
答案1
得分: 3
只需简单更改Jump函数的签名：
Jump(j Count)
然后你将得到预期的结果。
请参考kbd。
如果不更改，你将得到以下错误信息：
prog.go:15: invalid operation: *c += j (mismatched types Count and int)[process exited with non-zero status]
英文:
Simply change the Jump signature:
Jump(j Count)
And you will get the expected result.
See <kbd>play.golang.org</kbd>
If you don't, you would get:
prog.go:15: invalid operation: *c += j (mismatched types Count and int)[process exited with non-zero status]
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