C++ 'std::bad_alloc' what(): std::bad_alloc

Question

I am trying to run the below C++ code and I get this error: Could anyone please help me clarify why is this the issue Input: input/text_4.txt 9

terminate called after throwing an instance of 'std::bad_alloc' what(): std::bad_alloc Aborted (core dumped) After reading a few similar threads, the solution is to check dynamic memory allocation. However, my code does not have any dynamically allocated memory

input file text_4.txt:

This is because not very many happy things happened in the lives of the three Baudelaire youngsters.

Input: input/text_4.txt 8

Answer 1

When I run your code, on the i==16 iteration of the outer loop in arrangefile , we get width==8 and total==10 , with check==1 . As a result, even is initialized to -2 , and so the while(even--) loop is (nearly) infinite. So it attempts to add spaces to low until it runs out of memory.

(Note that the memory used by std::string is dynamically allocated, so your code does have dynamic memory allocation. The same for std::vector .)

I haven't analyzed your algorithm closely enough to figure out the correct fix, but it's possible your loop should be while(even-- > 0) instead.

---

I'll second the tip in the comments to use your debugger, and I'll repost the link: What is a debugger and how can it help me diagnose problems? . That's how I found this bug.

I ran the program under the debugger gdb . It ran for a few seconds, at which point I got suspicious because the program doesn't appear do anything complicated enough to take that much computation time. So I interrupted the program (Ctrl-C) which let me see where it was and what it was doing. I could see that it was within the while(even--) loop. That was also suspicious because that loop should complete very fast. So I inspected the value of even (with the command p even ) and saw that it was a large negative number. That could only happen if it had started as a negative number, which logically could only happen if total were greater than width . Inspecting their values I could see that this was indeed the case.

Maybe this will be helpful as you learn more about using your debugger.