Program Compiles Without Error, but Segfaults During Execution

Question

The following code compiles just fine but when I run it, it gets to the while loop and then SegFaults . The input file is a CSV file. What this program is supposed to take data from a CSV file and parse it into a structure, which is then sent to a function that prints it in a particular format to stdout.

Answer 1

Your airport pointer is null, so when you try to set elements of it, you dereference a null pointer. To fix, either give it automatic storage like so:

airPdata airport;

and pass it to printData like so:

printData(&airport)

Or allocate it with malloc:

airPdata *airport = malloc(sizeof(*airport));

But then make sure to free it when you are finished with it.

Also, just because your C program compiles does not mean it is correct, as you have seen. C is really unforgiving, especially with regards to memory, so you'll definitely need to pay close attention to how you handle memory, and maybe consider unit testing your program.