with this code i get an unexpected leak, no idea, where, when
#memory leak no idea where
dreamy raft
wise egretBOT
minor copper
did you try using asan?
dreamy raft
nope whats that
wise egretBOT
Memory errors in C and C++ are easy to make and they can be very hard to debug because they can manifest far from their source. Address sanitizer is a runtime checker that identifies memory errors at their source and makes debugging much simpler. Address sanitizer is available for gcc/clang on linux and msvc on windows. To use it simply pass -fsanitize=address to the compiler.
Note: Make sure to turn on debug symbols with
-gfor gcc/clang and-Zifor msvc.
dreamy raft
oh yeah i tried
minor copper
and?
dreamy raft
i cant replicate the error
but the program where i put the code finds an issue
if i knew where it happened it would be so much easier
minor copper
again - asan is the tool you should use to help you find said leak. please use it
if you don't like asan for whatever reason you can use valgrind instead
(in this particular case)
dreamy raft
yes i know, but no matter what i try to input i cant replicate the thing
minor copper
how do you know there is a leak in the first place then?
dreamy raft
the testing environment says there is
it has special edge cases it tests
but i cant replicate them
minor copper
i assume you don't have access to these edge cases then?
dreamy raft
yes
pale raven
with this code i get an unexpected leak, no idea, where, when
I'm on mobile. Can you paste code in chunks?
dreamy raft
uh sure i guess
#include <stdlib.h>
#define MAX_SIZE 100000
typedef struct {
long long from;
long long to;
long long daily_distribution;
long long daily_wage;
} Lorry;
typedef struct {
long long distribution;
long long price;
} Day;
Lorry makeLorry (long long from, long long to, long long daily_distribution, long long daily_wage) {
Lorry res = {from, to, daily_distribution, daily_wage};
return res;
}
int nespravnyVstup() {
printf("Nespravny vstup.\n");
return 1;
}
long long binarySearchDayByGoods(Day *arr, long long length, long long goods, long long initial_day) {
long long left = initial_day, right = length - 1;
long long result = -1;
while (left <= right) {
long long mid = left + (right - left) / 2;
if ((arr + mid)->distribution >= goods) {
result = mid;
right = mid - 1;
} else {
left = mid + 1;
}
}
return result;
}
int main(void) {
char spec = ' ', br_last = ' ';
unsigned length = 0;
Lorry lorry_list[MAX_SIZE];
long long last_day = 0;
printf("Moznosti dopravy:\n");
if (scanf(" %c", &spec) != 1 || spec != '{') return nespravnyVstup();
for(int i = 0; i < MAX_SIZE; i++) { // [ no - no , no , no ]
long long a, b, c, d = 0;
if (scanf(" [ %lld - %lld , %lld , %lld %c", &a, &b, &c, &d, &br_last) != 5 ||
a > b || a < 0 || b < 0 ||
c <= 0 || d <= 0 || br_last != ']') return nespravnyVstup();
lorry_list[i] = makeLorry(a, b, c, d);
if (b > last_day) last_day = b;
length++;
scanf(" %c", &spec);
if (spec == '}') break;
else if (spec == ',') continue;
else return nespravnyVstup();
}``` for (unsigned i = 0; i < length; i++) {
(list_of_days + lorry_list[i].from)->distribution += lorry_list[i].daily_distribution;
(list_of_days + lorry_list[i].from)->price += lorry_list[i].daily_wage;
if (lorry_list[i].to + 1 <= last_day) {
(list_of_days + (lorry_list[i].to + 1))->distribution += -lorry_list[i].daily_distribution;
(list_of_days + (lorry_list[i].to + 1))->price += -lorry_list[i].daily_wage;
}
}
long long total_price = 0, total_goods = 0, balance_price = 0, balance_goods = 0;
for (unsigned i = 0; i < last_day + 1; i++) {
//printf("ch %lld %lld\n", (list_of_days + i)->price, (list_of_days + i)->distribution);
balance_price += (list_of_days + i)->price;
balance_goods += (list_of_days + i)->distribution;
//printf("__%lld__%lld\n", balance_goods, balance_price);
total_price += balance_price;
total_goods += balance_goods;
(list_of_days + i)->price = total_price;
(list_of_days + i)->distribution = total_goods;
//printf("%d %lld %lld\n", i, total_price, total_goods);
}
long long max_cargo = (list_of_days + last_day)->distribution;
printf("Naklad:\n");
while(1) {
long long day = 0;
long long goods = 0;
int out = scanf(" %lld %lld", &day, &goods);
if (out != 2 || day < 0 || goods <= 0) {
if (out == EOF) {
free(list_of_days);
list_of_days = NULL;
return 0;
}
printf("Nespravny vstup.\n");
free(list_of_days);
list_of_days = NULL;
return 0;
}``` if (day == 0) {
zero_day_goods = 0;
zero_day_price = 0;
} else {
zero_day_goods = (list_of_days + (day - 1))->distribution;
zero_day_price = (list_of_days + (day - 1))->price;
}
zero_day_goods += goods;
if (zero_day_goods > max_cargo) {
printf("Prilis velky naklad, nelze odvezt.\n");
continue;
}
long long new_day = binarySearchDayByGoods(list_of_days, last_day + 1, zero_day_goods, day);
if (new_day == -1) {
printf("Prilis velky naklad, nelze odvezt.\n");
continue;
}
long long new_price = (list_of_days + new_day)->price - zero_day_price;
printf("Konec: %lld, cena: %lld\n", new_day, new_price);
}
}```if (out != 2 || day < 0 || goods <= 0) {
if (out == EOF) {
free(list_of_days);
list_of_days = NULL;
return 0;
}
printf("Nespravny vstup.\n");
free(list_of_days);
list_of_days = NULL;
return 0;
}```
is a bit strange don't you think.  is equivalent to:
```c
if (out != 2 || day < 0 || goods <= 0) {
if (out != EOF) {
printf("Nespravny vstup.\n");
}
free(list_of_days);
list_of_days = NULL;
return 0;
}```
no?
in any case - i personally fail to see a scenario in which case the loop exits (normally) while failing to `free` `list_of_days`same
its a bitly strangely set ye
but there is something
no idea what
might be something with the array
minor copper
well... unless the program crashes before it reached the loop 🙂
is there a possibility you access any of your arrays out of bounds in the section above the loop?
pale raven
What's the objective of your program?
gaunt hound
Could it be that the testing environment is doing something as simple as counting the number of calloc and free calls? Your code has two free calls and one calloc call though the execution path will never execute both of them. Just a thought.
still dove
write lots of assertions. a lot!
dreamy raft
!solved