用C ++编写二进制搜索树到文件

I have created a binary search tree which gets a text file inputted into it and then puts it in alphabetical order, I am able to print the tree straight to the console but when i try and write it to a text file all i get is gibberish, is there anyway i can do this using fprintf(fp, "%s",rootPtr->word );? or should i be putting each rootPtr->word into an array and then write that array to the file?I have created a binary search tree which gets