EDIT: Full code has now been posted so u can compile.

So we're a few first semester software students kind of stuck on a problem regarding structs in c. Stack overflow has helped me so many times already, so figured I'd actually try asking this time, as i couldn't seem to find what im looking for.

Our logic (see code below):

1. Main calls empty_trash
2. empty_trash (in its parameter) calls compare_trash
3. Compare trash parses through 4 areas (structs)
4. Compare trash checks if the average of our data is over a margin, if so checks if that average is higher than firstly our empty struct, which presumably has 0 average, and then if a higher is found that one. This leaves us with the index of the struct with the highest average
5. Compare trash returns this struct to empty trash, and an int pointer of the index to main.
6. empty trash then goes through the subareas and checks their average of data and resets the ones over margin2
7. we return the reset area to main
8. in main we have an array of our structs 1-4. We assign the area returned from empty trash to arrayofstructs[index pointed back]

In our minds the logic makes sense, but it seems it's not working as our program crashes at the line in main. We think it's because we don't assign the struct correctly in main, but not 100% sure.

We're kinda baffled as both of these functions work fine on their own when we tested them seperately, but together they do not.

Any help would be much appreciated <3

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

#define MARGIN 70
#define MARGIN2 30
#define SIZE 5

struct subarea
{
   int co2_cost, time;
   double average, sensorData[SIZE];
};

struct area
{
   struct subarea sub_area1, sub_area2, sub_area3, sub_area4;
   double average;
};

struct area simmulated_days(struct area area, int lower_random, int upper_random);
struct area average_trash(struct area area);
struct area sensor_data_start(struct area area1);
struct area compare_trash_to_empty(struct area area1, struct area area2, struct area area3, struct area area4, int *);
struct area empty_trash(struct area chosen_area, int *co2_counter_p, int *time_counter_p);

int main(void)
{
   int co2_counter, time_counter;
   int day_counter = 0;
   int *co2_counter_p = &co2_counter;
   int *time_counter_p = &time_counter;
   int area_number;
   srand(time(NULL));

   struct subarea subarea1_1 = {50, 50, 0, {}};
   struct subarea subarea1_2 = {50, 50, 0, {}};
   struct subarea subarea1_3 = {50, 50, 0, {}};
   struct subarea subarea1_4 = {50, 50, 0, {}};
   struct area area1 = {subarea1_1, subarea1_2, subarea1_3, subarea1_4, 0};

   struct subarea subarea2_1 = {50, 50, 0, {}};
   struct subarea subarea2_2 = {50, 50, 0, {}};
   struct subarea subarea2_3 = {50, 50, 0, {}};
   struct subarea subarea2_4 = {50, 50, 0, {}};
   struct area area2 = {subarea2_1, subarea2_2, subarea2_3, subarea2_4, 0};

   struct subarea subarea3_1 = {50, 50, 0, {}};
   struct subarea subarea3_2 = {50, 50, 0, {}};
   struct subarea subarea3_3 = {50, 50, 0, {}};
   struct subarea subarea3_4 = {50, 50, 0, {}};
   struct area area3 = {subarea3_1, subarea3_2, subarea3_3, subarea3_4, 0};

   struct subarea subarea4_1 = {50, 50, 0, {}};
   struct subarea subarea4_2 = {50, 50, 0, {}};
   struct subarea subarea4_3 = {50, 50, 0, {}};
   struct subarea subarea4_4 = {50, 50, 0, {}};
   struct area area4 = {subarea4_1, subarea4_2, subarea4_3, subarea4_4, 0};

   struct area useless_area = {};
   struct area all_areas[5] = {useless_area, area1, area2, area3, area4};
   struct area local_area = {};

   area1 = sensor_data_start(area1);
   area2 = sensor_data_start(area2);
   area3 = sensor_data_start(area3);
   area4 = sensor_data_start(area4);

   int running = 1;
   while (running)
   {
       area1 = simmulated_days(area1, 7, 10);
       area2 = simmulated_days(area2, 4, 7);
       area3 = simmulated_days(area3, 9, 12);
       area4 = simmulated_days(area4, 6, 9);

       for (int i = 0; i < SIZE; i  )
       {
           printf("%lf  |  %lf  |  %lf  |  %lf  |\n", area1.sub_area1.sensorData[i], area2.sub_area1.sensorData[i], area3.sub_area1.sensorData[i], area4.sub_area1.sensorData[i]);
       }

       day_counter  ;
       printf("Day %d\n", day_counter);

       area1 = average_trash(area1);
       area2 = average_trash(area2);
       area3 = average_trash(area3);
       area4 = average_trash(area4);

       printf("hihi\n");
       all_areas[area_number] = empty_trash(compare_trash_to_empty(area1, area2, area3, area4, &area_number), co2_counter_p, time_counter_p);

       printf("titi\n");
       for (int i = 0; i < SIZE; i  )
       {
           printf("Local area %lf\t", local_area.sub_area1.sensorData[i]);
       }
       printf("\n");

       if (day_counter == 2)
       {
           running = 0;
       }
   }
}

struct area simmulated_days(struct area area, int lower_random, int upper_random)
{
   for (int i = 0; i < SIZE; i  )
   {
       area.sub_area1.sensorData[i]  = ((rand() % (upper_random - lower_random   1))   lower_random);
       area.sub_area2.sensorData[i]  = ((rand() % (upper_random - lower_random   1))   lower_random);
       area.sub_area3.sensorData[i]  = ((rand() % (upper_random - lower_random   1))   lower_random);
       area.sub_area4.sensorData[i]  = ((rand() % (upper_random - lower_random   1))   lower_random);
   }
   return area;
}

//Average Trash Function
struct area average_trash(struct area area)
{
   double sum1 = 0, sum2 = 0, sum3 = 0, sum4 = 0;

   for (int i = 0; i < SIZE; i  )
   {
       sum1  = area.sub_area1.sensorData[i];
       sum2  = area.sub_area2.sensorData[i];
       sum3  = area.sub_area3.sensorData[i];
       sum4  = area.sub_area4.sensorData[i];
   }
   area.sub_area1.average = sum1 / SIZE;
   area.sub_area2.average = sum2 / SIZE;
   area.sub_area3.average = sum3 / SIZE;
   area.sub_area4.average = sum4 / SIZE;
   area.average = (area.sub_area1.average   area.sub_area2.average   area.sub_area3.average   area.sub_area4.average) / 4;

   return area;
}

struct area sensor_data_start(struct area area1)
{
   double x = 75;

   for (int i = 0; i < SIZE; i  )
   {
       area1.sub_area1.sensorData[i] = x;
       area1.sub_area2.sensorData[i] = x;
       area1.sub_area3.sensorData[i] = x;
       area1.sub_area4.sensorData[i] = x;
   }
   return area1;
}

struct area compare_trash_to_empty(struct area area1, struct area area2, struct area area3, struct area area4, int *area_number_p)
{
   struct area local_area = {};
   int i, highBlock = 0;
   struct area block[5] = {local_area, area1, area2, area3, area4};

   for (i = 1; i <= 4; i  )
   {
       if (block[i].average >= MARGIN)
       {
           if (block[i].average > block[highBlock].average)
           {
               highBlock = i;
           }
       }
   }
   *area_number_p = highBlock;
   return block[highBlock];
}

struct area empty_trash(struct area chosen_area, int *co2_counter_p, int *time_counter_p)
{
   int co2_counter = 0;
   int time_counter = 0;
   
   if (chosen_area.sub_area1.average > MARGIN2)
   {
       co2_counter  = chosen_area.sub_area1.co2_cost;
       time_counter  = chosen_area.sub_area1.time;
       chosen_area.sub_area1.average = 0;
       for (int i = 0; i < SIZE; i  )
       {
           chosen_area.sub_area1.sensorData[i] = 0;
           printf("ET %lf\t", chosen_area.sub_area1.sensorData[i]);
       }
       printf("\n");
   }
   if (chosen_area.sub_area2.average > MARGIN2)
   {
       co2_counter  = chosen_area.sub_area2.co2_cost;
       time_counter  = chosen_area.sub_area2.time;
       chosen_area.sub_area2.average = 0;
       for (int i = 0; i < SIZE; i  )
       {
           chosen_area.sub_area2.sensorData[i] = 0;
       }
   }
   if (chosen_area.sub_area3.average > MARGIN2)
   {
       co2_counter  = chosen_area.sub_area3.co2_cost;
       time_counter  = chosen_area.sub_area3.time;
       chosen_area.sub_area3.average = 0;
       for (int i = 0; i < SIZE; i  )
       {
           chosen_area.sub_area3.sensorData[i] = 0;
       }
   }
   if (chosen_area.sub_area4.average > MARGIN2)
   {
       co2_counter  = chosen_area.sub_area4.co2_cost;
       time_counter  = chosen_area.sub_area4.time;
       chosen_area.sub_area4.average = 0;
       for (int i = 0; i < SIZE; i  )
       {
           chosen_area.sub_area4.sensorData[i] = 0;
       }
   }

   *co2_counter_p = co2_counter;
   *time_counter_p = time_counter;
   return chosen_area;
}

CodePudding user response：

My original comment:

Side note: Whenever I see (e.g.) v1 v2 v3 v4 v5 I want to replace it with an array v[5]. So, in struct area, you want: struct subarea sub_area[5]; This will greatly simplify your code. You already do this in main – Craig Estey

Your response:

@Craig Estey Ye don't have a huge experience with debuggers yet, usually just use printfs, but sounds very helpful so ill youtube a guide side note: very helpful we didn't foresee this at first but would simplify so much, ty4input – Thybo

I've done better(?) I've done the preliminary restructuring of your code. I believe this will be helpful to others in addition to yourselves.

I'm sorry, but (and I'm saying this with kindness), the code needs a lot of restructuring. The sheer [needless] complexity could be masking numerous bugs.

Things to note:

1. Passing a struct by value is hazardous. It is legal, but it makes the code complicated. Passing by pointer is 99.44% of the time better. You can just modify the given struct "in-place" rather than having to return it [again, by value].
2. Learn about iterating through an array by using a pointer to the "current" element instead of an index. You'll see this in the FORALL loop below.
3. Don't "replicate" code. Notice what happens when using arrays. Instead of (e.g) four copies of the code, we have one
4. Instead of 4 areas (e.g. area1, area2, area3, area4), if we had 10,000 areas. Would you replicate the code 10,000 times as was done in (e.g.) empty_trash?
5. I added typedef for your two struct to simplify things a bit.
6. I've added a few advanced techniques, such as the use of the FORALL macro to traverse arrays.

I've used preprocessor conditionals to denote old code vs new:

#if 0
// old code
#else
// new code
#endif

I've done some/most of the editing. I've compiled it. I could have made a zillion mistakes. But, it should give you the idea:

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

#define MARGIN      70
#define MARGIN2     30
#define SIZE        5

#define NAREA       4

typedef struct subarea {
    int co2_cost, time;
    double average, sensorData[SIZE];
} subarea_t;

typedef struct area {
#if 0
    struct subarea sub_area1, sub_area2, sub_area3, sub_area4;
#else
    subarea_t sub_area[NAREA];
#endif
    double average;
} area_t;

#define COUNTOF(_arr) \
    (sizeof(_arr) / sizeof(_arr[0]))
#define FORALL(_ptr,_arr) \
    __typeof__(_arr[0]) *_ptr = &_arr[0];  _ptr < &_arr[COUNTOF(_arr)];    _ptr

void
simulated_days(area_t *area, int lower_random, int upper_random)
{

    for (FORALL(sub,area->sub_area)) {
        for (FORALL(data,sub->sensorData)) {
            *data  = ((rand() % (upper_random - lower_random   1))  
                lower_random);
        }
    }
}

//Average Trash Function
void
average_trash(area_t *area)
{
    double sum[NAREA] = { 0 };
    int i;

#if 0
    for (int i = 0; i < SIZE; i  ) {
        sub[i] = a
        sum1  = area.sub_area1.sensorData[i];
        sum2  = area.sub_area2.sensorData[i];
        sum3  = area.sub_area3.sensorData[i];
        sum4  = area.sub_area4.sensorData[i];
    }
#else
    for (FORALL(sub,area->sub_area),   i) {
        i = 0;
        for (FORALL(data,sub->sensorData),   i)
            sum[i]  = *data;
    }
#endif

#if 0
    area.sub_area1.average = sum1 / SIZE;
    area.sub_area2.average = sum2 / SIZE;
    area.sub_area3.average = sum3 / SIZE;
    area.sub_area4.average = sum4 / SIZE;
#else
    i = 0;
    for (FORALL(sub,area->sub_area),   i)
        sub->average = sum[i] / SIZE;
#endif

#if 0
    area.average = (area.sub_area1.average  
        area.sub_area2.average  
        area.sub_area3.average  
        area.sub_area4.average) / 4;
#else
    area->average = 0;

    for (FORALL(sub,area->sub_area))
        area->average  = sub->average;

    area->average /= NAREA;
#endif
}

#if 0
area_t
sensor_data_start(area_t area1)
{
    double x = 75;

    for (int i = 0; i < SIZE; i  ) {
        area1.sub_area1.sensorData[i] = x;
        area1.sub_area2.sensorData[i] = x;
        area1.sub_area3.sensorData[i] = x;
        area1.sub_area4.sensorData[i] = x;
    }
    return area1;
}
#else
void
sensor_data_start(area_t *area)
{
    double x = 75;

    for (FORALL(sub,area->sub_area)) {
        for (FORALL(data,sub->sensorData))
            *data = x;
    }
}
#endif

#if 0
area_t
compare_trash_to_empty(area_t area1, area_t area2, area_t area3, area_t area4, int *area_number_p)
{
    area_t local_area = { };
    int i,
     highBlock = 0;
    area_t block[5] = { local_area, area1, area2, area3, area4 };

    for (i = 1; i <= 4; i  ) {
        if (block[i].average >= MARGIN) {
            if (block[i].average > block[highBlock].average) {
                highBlock = i;
            }
        }
    }
    *area_number_p = highBlock;
    return block[highBlock];
}
#else
area_t *
compare_trash_to_empty(const area_t *blocks, area_t *all_areas)
{
    area_t local_area = { };
    int i, highBlock = 0;
#if 0
    area_t block[5] = { local_area, area1, area2, area3, area4 };
#else
    const area_t *block;
#endif

    for (i = 1;  i < NAREA;    i) {
        block = &blocks[i];
        if (block->average >= MARGIN) {
            if (block->average > blocks[highBlock].average)
                highBlock = i;
        }
    }

    all_areas[highBlock] = blocks[highBlock];

    return &all_areas[highBlock];
}
#endif

#if 0
area_t
empty_trash(area_t chosen_area, int *co2_counter_p, int *time_counter_p)
{
    int co2_counter = 0;
    int time_counter = 0;

    if (chosen_area.sub_area1.average > MARGIN2) {
        co2_counter  = chosen_area.sub_area1.co2_cost;
        time_counter  = chosen_area.sub_area1.time;
        chosen_area.sub_area1.average = 0;
        for (int i = 0; i < SIZE; i  ) {
            chosen_area.sub_area1.sensorData[i] = 0;
            printf("ET %lf\t", chosen_area.sub_area1.sensorData[i]);
        }
        printf("\n");
    }
    if (chosen_area.sub_area2.average > MARGIN2) {
        co2_counter  = chosen_area.sub_area2.co2_cost;
        time_counter  = chosen_area.sub_area2.time;
        chosen_area.sub_area2.average = 0;
        for (int i = 0; i < SIZE; i  ) {
            chosen_area.sub_area2.sensorData[i] = 0;
        }
    }
    if (chosen_area.sub_area3.average > MARGIN2) {
        co2_counter  = chosen_area.sub_area3.co2_cost;
        time_counter  = chosen_area.sub_area3.time;
        chosen_area.sub_area3.average = 0;
        for (int i = 0; i < SIZE; i  ) {
            chosen_area.sub_area3.sensorData[i] = 0;
        }
    }
    if (chosen_area.sub_area4.average > MARGIN2) {
        co2_counter  = chosen_area.sub_area4.co2_cost;
        time_counter  = chosen_area.sub_area4.time;
        chosen_area.sub_area4.average = 0;
        for (int i = 0; i < SIZE; i  ) {
            chosen_area.sub_area4.sensorData[i] = 0;
        }
    }

    *co2_counter_p = co2_counter;
    *time_counter_p = time_counter;
    return chosen_area;
}
#else
void
empty_trash(area_t *chosen_area, int *co2_counter_p, int *time_counter_p)
{
    int co2_counter = 0;
    int time_counter = 0;

    for (FORALL(sub,chosen_area->sub_area)) {
        if (sub->average > MARGIN2) {
            co2_counter  = sub->co2_cost;
            time_counter  = sub->time;
            for (FORALL(data,sub->sensorData))
                *data = 0;
        }
    }

    *co2_counter_p = co2_counter;
    *time_counter_p = time_counter;
}
#endif

int
main(void)
{
    int co2_counter, time_counter;
    int day_counter = 0;
    int *co2_counter_p = &co2_counter;
    int *time_counter_p = &time_counter;
    int area_number;

    srand(time(NULL));

#if 0
    subarea_t subarea1_1 = { 50, 50, 0, {} };
    subarea_t subarea1_2 = { 50, 50, 0, {} };
    subarea_t subarea1_3 = { 50, 50, 0, {} };
    subarea_t subarea1_4 = { 50, 50, 0, {} };
    area_t area1 = { subarea1_1, subarea1_2, subarea1_3, subarea1_4, 0 };

    subarea_t subarea2_1 = { 50, 50, 0, {} };
    subarea_t subarea2_2 = { 50, 50, 0, {} };
    subarea_t subarea2_3 = { 50, 50, 0, {} };
    subarea_t subarea2_4 = { 50, 50, 0, {} };
    area_t area2 = { subarea2_1, subarea2_2, subarea2_3, subarea2_4, 0 };

    subarea_t subarea3_1 = { 50, 50, 0, {} };
    subarea_t subarea3_2 = { 50, 50, 0, {} };
    subarea_t subarea3_3 = { 50, 50, 0, {} };
    subarea_t subarea3_4 = { 50, 50, 0, {} };
    area_t area3 = { subarea3_1, subarea3_2, subarea3_3, subarea3_4, 0 };

    subarea_t subarea4_1 = { 50, 50, 0, {} };
    subarea_t subarea4_2 = { 50, 50, 0, {} };
    subarea_t subarea4_3 = { 50, 50, 0, {} };
    subarea_t subarea4_4 = { 50, 50, 0, {} };
    area_t area4 = { subarea4_1, subarea4_2, subarea4_3, subarea4_4, 0 };
#else
    area_t areamain[NAREA];

    for (FORALL(area,areamain)) {
        for (FORALL(sub,area->sub_area)) {
            sub->co2_cost = 50;
            sub->time = 50;
            sub->average = 50;
            for (FORALL(data,sub->sensorData))
                *data = 0.0;
        }
    }
#endif

#if 0
    area_t useless_area = { };
    area_t all_areas[5] = { useless_area, area1, area2, area3, area4 };
#else
    area_t *all_areas = areamain;
#endif
    area_t local_area = { };

#if 0
    area1 = sensor_data_start(area1);
    area2 = sensor_data_start(area2);
    area3 = sensor_data_start(area3);
    area4 = sensor_data_start(area4);
#else
    for (FORALL(area,areamain))
        sensor_data_start(area);
#endif

    int running = 1;

    while (running) {
        simulated_days(&areamain[0], 7, 10);
        simulated_days(&areamain[1], 4, 7);
        simulated_days(&areamain[2], 9, 12);
        simulated_days(&areamain[3], 6, 9);

#if 0
        for (int i = 0; i < SIZE; i  ) {
            printf("%lf  |  %lf  |  %lf  |  %lf  |\n",
                area1.sub_area1.sensorData[i],
                area2.sub_area1.sensorData[i],
                area3.sub_area1.sensorData[i],
                area4.sub_area1.sensorData[i]);
        }
#else
        for (int i = 0; i < SIZE; i  ) {
            for (FORALL(area,areamain))
                printf("%lf  |",area->sub_area[i]);
            printf("\n");
        }
#endif

        day_counter  ;
        printf("Day %d\n", day_counter);

#if 0
        area1 = average_trash(area1);
        area2 = average_trash(area2);
        area3 = average_trash(area3);
        area4 = average_trash(area4);
#else
        for (FORALL(area,areamain))
            average_trash(area);
#endif

        printf("hihi\n");
#if 0
        all_areas[area_number] =
            empty_trash(compare_trash_to_empty(area1, area2, area3, area4,
                &area_number), co2_counter_p, time_counter_p);
#else
        area_t *area_out = compare_trash_to_empty(areamain,all_areas);
        empty_trash(area_out, co2_counter_p, time_counter_p);
#endif

        printf("titi\n");
#if 0
        for (int i = 0; i < SIZE; i  ) {
            printf("Local area %lf\t", local_area.sub_area1.sensorData[i]);
        }
        printf("\n");
#else
        do {
            subarea_t *sub = area_out->sub_area;
            printf("Local area ");
            for (FORALL(data,sub->sensorData))
                printf("%f\t", *data);
            printf("\n");
        } while (0);
#endif

        if (day_counter == 2) {
            running = 0;
        }
    }
}