# btreeinsertdata ## Instructions Write a function that applies a function in order to each element in the tree (see in order tree walks) ## Expected function ```go func BTreeApplyInorder(root *piscine.TreeNode, f func(...interface{}) (int, error)) { } ``` ## Usage Here is a possible [program](TODO-LINK) to test your function : ```go package main import ( "fmt" piscine "." ) func main() { root := &piscine.TreeNode{Data: "4"} piscine.BTreeInsertData(root, "1") piscine.BTreeInsertData(root, "7") piscine.BTreeInsertData(root, "5") BTreeApplyInorder(root, fmt.Println) } ``` And its output : ```console student@ubuntu:~/piscine/btreeinsertdata$ go build student@ubuntu:~/piscine/btreeinsertdata$ ./btreeinsertdata 1 4 5 7 student@ubuntu:~/piscine/btreeinsertdata$ ```