我一直有分割错误，我不知道为什么

I'm writing a linked list program in C and I'm stuck trying to write the linked list to a file. After the program asks the user what name they want to save the file under I enter the name and hit ENTER and then I get a segmentation fault and the program quits. I am lost trying to figure out why. The only thing I can think of is the I'm writing a linked list program in C and I'm