Go: using a pointer to array
下面的不是指针指向数组,而是指针指向Slice
I'm having a little play with google's Go language, and I've run into something which is fairly basic in C but doesn't seem to be covered in the documentation I've seen so far.
When I pass a pointer to an array to a function, I presumed we'd have some way to access it as follows:
func conv(x []int, xlen int, h []int, hlen int, y *[]int) for i := 0; i<xlen; i++ { for j := 0; j<hlen; j++ { *y[i+j] += x[i]*h[j] } } }
But the Go compiler doesn't like this:
sean@spray:~/dev$ 8g broke.go broke.go:8: invalid operation: y[i + j] (index of type *[]int)
Fair enough - it was just a guess. I have got a fairly straightforward workaround:
func conv(x []int, xlen int, h []int, hlen int, y_ *[]int) { y := *y_ for i := 0; i<xlen; i++ { for j := 0; j<hlen; j++ { y[i+j] += x[i]*h[j] } } }
But surely there's a better way. The annoying thing is that googling for info on Go isn't very useful as all sorts of C\C++\unrelated results appear for most search terms.
下面是解决方案:
the semicolon and the asterisk are added and removed.
*y[i+j] += x[i]*h[j] --> (*y)[i+j] += x[i] * h[j];