在元素中定位元素并在C中进行比较

I'm having trouble with what I think is a segfault when I attempt to access a specific element of a string. Specifically, I'm trying to determine the letter at the end of 'longitude' and check whether it's a 'W' or not. However, I end up crashing before I even get to the strcmp part. Here's the code:I'm having trouble with what I think is a segfa