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#Unwanted change to array value
warm rootBOT
upbeat perch
int res[arraySize][arraySize] this does not bring me pleasure
but
what are x and y
what is the size of this array
is that x is 1 and y is 3
where are you printing this from?
well I guess youll never learn
rip
warm rootBOT
@river delta Has your question been resolved? If so, type !solved :)
upbeat perch
try debugging and seeing what the values of i and j are
well
no you printed them
honestly idk this looks like classic undefined behaviour
which can be really hard to track down sometimes and idk realllly what all the values are
shrewd apex
When compiling with -Og -g3 -Wall -Wextra -Wpedantic -fsanitize=address,undefined -Wpedantic I get the following output:
<source>: In function 'bestVerticalCut':
<source>:164:16: warning: 'bestVal' may be used uninitialized [-Wmaybe-uninitialized]
164 | if (aux > bestVal)
| ^
<source>:161:9: note: 'bestVal' was declared here
161 | int bestVal, aux = 0;
| ^~~~~~~
Program returned: 0
Program stdout
Array with the pieces:
1 1 5
1 3 10
i: 1, j: 2
res[0][0]: 5
i: 1, j: 2
res[0][0]: 5
res[0][0]: 10
10, 10, 10
Result: 20
Program stderr
/app/example.c:78:11: runtime error: index 3 out of bounds for type 'int [*]'
/app/example.c:94:16: runtime error: index 2 out of bounds for type 'int [*]'
/app/example.c:108:17: runtime error: index 0 out of bounds for type 'int [*]'
/app/example.c:109:17: runtime error: index 0 out of bounds for type 'int [*]'
/app/example.c:95:24: runtime error: index 0 out of bounds for type 'int [*]'
/app/example.c:117:41: runtime error: index 0 out of bounds for type 'int [*]'
/app/example.c:118:17: runtime error: index 1 out of bounds for type 'int [*]'
/app/example.c:120:41: runtime error: index 0 out of bounds for type 'int [*]'
/app/example.c:121:17: runtime error: index 0 out of bounds for type 'int [*]'
/app/example.c:122:41: runtime error: index 0 out of bounds for type 'int [*]'
/app/example.c:123:60: runtime error: index 0 out of bounds for type 'int [*]'
/app/example.c:123:49: runtime error: index 1 out of bounds for type 'int [*]'
/app/example.c:123:38: runtime error: index 0 out of bounds for type 'int [*]'
/app/example.c:79:34: runtime error: index 3 out of bounds for type 'int [*]'
So it appears there are a few out of bounds accesses and your bestVal variable is used uninitialized
Here's the according godbolt with the line numbers, or you can just compile it for yourself with the options I've named above
shrewd apex
No, it says it was "declared".
Declaration
int x;
Declaration and Initialization:
int x = 4;
```Assignment:
```c
x = 4;
```Declaration and Assignment:
```c
int x;
x = 4;
🐒
shrewd apex
I'll try to figure it out after a smoke break.
In the meantime could you just give me an explanation on what your code even does so that I can understand and follow it better?
shrewd apex
Okay, so the first false index access is in the line
res[X][Y] = bestValue(X, Y, res, pieces, n);
Here X and Y describe the size of the array, so the maximum index one could use is X - 1 and Y - 1 respectively, meaning you're accessing out of bounds.
Also arraySize is uninitialized when you first access it in bestValue, as in your main you merely declared and initialized a local variable, rather than changing the global one.
Except the compiler doesn't complain about it because global variables are default-initialized, so in that case arraySize would be 0 everywhere except for inside the main function
Haven't looked over all yet but I'm sure that could lead to some problems
warm rootBOT