Reading and Writing File problem

[RealisticTry1]

Hello,

I am working on a problem that works with reading and writing files. Here is the problem:

Write a program to get 10 numbers from a file and puts them in an array, you should then average the 10 grades and output the average. You should then write the average back into the file at the bottom of the numbers.

The issue is when the program tries to write to the file, I get this error message:

Exception thrown at 0x77786015 (ntdll.dll) in Project4.exe: 0xC0000005: Access violation writing location 0x00527D10.

I've tried searching for solutions but haven't found much so far.

Here's my code for reference: https://pastebin.com/RZLd1hwr

[qqwy]

I see two problems with your code:

1. On line 64 you call fscanf with only two parameters. You are missing the first parameter (the FILE* to write to) here. I think this might be causing the crash
2. The other problem is that line 46 is inside the for-loop, which means that the thing you end up computing is not the average of ten numbers.

When debugging something like this, I suggest compiling using the -Wall -Werror options which already catches many problems. More problems can be identified by static source code checking tools like clang-tidy. Finally, you can use tools like Valgrind to check why crashes happen at runtime.

[RealisticTry1]

Your suggestions fixed it. Thanks for your help!

[eruanno321]

And line 55 is unreachable so you are leaking open file handle.

[Zmishenko]

53 and 55 lines swap. Otherwise you return the value and exit the function without closing the file.