Defining a function that returns a slice of variable size in golang
First of all, slices are already of “variable size”: [100]int and […]int are array type definitions.
[]int is the correct syntax for a slice, and you could implement the function as:
func BuildSlice(size int) []int {
return make([]int, size)
}The built-in function make takes a type T, which must be a slice, map or channel type, optionally followed by a type-specific list of expressions. It returns a value of type T (not *T). The memory is initialized as described in the section on initial values. Call Type T Result make(T, n) slice slice of type T with length n and capacity n make(T, n, m) slice slice of type T with length n and capacity m The size arguments n and m must be of integer type or untyped. A constant size argument must be non-negative and representable by a value of type int. If both n and m are provided and are constant, then n must be no larger than m. If n is negative or larger than m at run time, a run-time panic occurs. s := make([]int, 10, 100) // slice with len(s) == 10, cap(s) == 100 s := make([]int, 1e3) // slice with len(s) == cap(s) == 1000 s := make([]int, 1<<63) // illegal: len(s) is not representable by a value of type int s := make([]int, 10, 0) // illegal: len(s) > cap(s)
func obtainNext(str string) []int {
sLen := len(str)
next := make([]int, sLen)
next[0] = -1
k, j := -1, 0
for j < sLen-1 {
if k == -1 || str[j] == str[k] {
k++
j++
next[j] = k
} else {
k = next[k]
}
}
return next
}