Using a separate function to initialize a struct array

Question

I've been searching all over the place, but all I could find is things on initializing a struct array, not in another function. This is my old homework assignment. My assignment was to read commands from a text file, store them into an array and pipe the commands into a program called sketchpad. I actually feel that I should have initialized/reinitialized my struct array in another function because there is an end command in the text file (i thought there was nothing after that end command). Looking it over, I forgot to cater to that fact that you could read two text files in one consecutively. There are other ways of doing it, the teacher showed us a way in class to cater to it. But I would like to know how to do it my way. How would you call a function that initializes/reinitializes a struct array and send the values back to the place it was called? We use pointers right? How would we go about doing it?

Here is my code:

void fileParsing(FILE * fp, FILE* pipe)
{
   /*defines and initializes the commands being searched and counted */
   int Figure =0;
   int draw =0;
   int End =0;
   int printFigure =0;
   int drawFigure =0;
   int translate =0;
   int child =0;
   int comment =0;
   int i, j;

   struct figure array_figure[19];  //WTF!!!! WHY 19?????
   //assigns absurd values to array to distinguish when to stop looking for coordinates
   for(i=0; i < FIGURE_MAX; ++i)
   {
      memset(array_figure[i].name, 0, LINE_LEN);
      for(j=0; j<POINTS_MAX; ++j)
      {
         array_figure[i].Coord[j].xcoor = fup_value;
         array_figure[i].Coord[j].ycoor =fup_value;
      }
   }
   //array_figure[15].name = "adsfsdf";

   //printf("\n%d",array_figure[0].Coord[0].xcoor);
   int count = 0;
   int count2 = 0;
   int drawCount = 0;
   int reset;
   //if(reset = 0; reset < 256; reset++);
   //strncpy(array_figure[count].name, "0", LINE_LEN);

   //printf("about to go into a while loop\n");

   while(fgets(line, LINE_LEN, fp)!=NULL)
   {
      sscanf(line, "%s%s%d%d", command, name, &x, &y);

      //looks for commands and organizes them accordingly
      if(strncmp(command, "Figure", 6) == 0)
      {
         printf("Found a Figure command\n");
         sscanf(line, "%s%s%d%d", command, name, &x, &y);

         originX = x;
         originY = y;

         //assigns name and initial point
         strncpy(array_figure[count2].name, name, LINE_LEN);
         array_figure[count2].Coord[count].xcoor = x; //change: count2 from '3' from array_figure[i]
         array_figure[count2].Coord[count].ycoor = y;
         //printf("%s: %lf, %lf\n", array_figure[count2].name, array_figure[count2].Coord[count].xcoor, array_figure[count2].Coord[count].ycoor);

         count++;
         //printf("%d\n", count);

         //fprintf(output, "%d  %d\n", x, y); //MIGHT BE NEEDED!
         //originX = x;
         //originY = y;
      }

      else if(strncmp(command, "draw", 5) == 0)
      {
         printf("Found a draw command\n");
         sscanf(line, "%s%d%d", command, &x, &y);
         //strncpy(array_figure[count].name, "0", LINE_LEN);

         //priFiguntf("%s\n", array_figure[2].name);

         //creates a new origin coordinate
         originX = array_figure[count2].Coord[count-1].xcoor;
         originY = array_figure[count2].Coord[count-1].ycoor;

         //assigns more coordinates
         array_figure[count2].Coord[count].xcoor = originX + x;
         array_figure[count2].Coord[count].ycoor = originY + y;
         //printf("%lf, %lf\n", array_figure[count2].Coord[count].xcoor, array_figure[count2].Coord[count].ycoor);
         //printf("%c\n", array_figure[count]);

         count++;
         //printf("%d\n", count);
      }

      else if(strncmp(command, "drawFigure", 10) == 0)
      {
         printf("Found a drawFigure command\n");
         sscanf(line,"%s%s\n", command, name);
         //if statement; iterates through to with strncmp to find figure name to draw

         //printf("%s\n", name);
         drawFigureCount= 0;
         //checks for which element matchs the specified name for drawing
         while(
            strncmp(array_figure[drawFigureCount].name, name, LINE_LEN) != 0 &&
            drawFigureCount < FIGURE_MAX)
            drawFigureCount++;

         if(drawFigureCount < FIGURE_MAX)
         {
            //printf("\tstartingX/Y assign\n");
            startingX = array_figure[drawFigureCount].Coord[0].xcoor;
            startingY = array_figure[drawFigureCount].Coord[0].ycoor;
            //printf("\tdone - startingX/Y assign\n");
            //sends coordinates to sketchpad
            for(i=1; i< POINTS_MAX; ++i)
            {
               if(array_figure[drawFigureCount].Coord[i].xcoor != fup_value &&
                  array_figure[drawFigureCount].Coord[i].ycoor != fup_value)
               {
                  //printf("\t\tdraw segment sent to output\n");
                  fprintf(pipe,
                     "drawSegment %ld %ld %ld %ld\n",
                     lround(startingX), lround(startingY),
                     lround(array_figure[drawFigureCount].Coord[i].xcoor),
                     lround(array_figure[drawFigureCount].Coord[i].ycoor)
                     );
                  //printf("\t\tdone - draw segment sent to output\n");

                  //printf("\t\tstartingX/Y update\n");
                  startingX = array_figure[drawFigureCount].Coord[i].xcoor;
                  startingY = array_figure[drawFigureCount].Coord[i].ycoor;
                  //printf("\t\tdone - startingX/Y update\n");

               } else break;
            }
            //printf("\tbroke out of the loop or the loop ended\n");
         }
      }

      //checks for "end" in the input file to know when to stop making coordinates for a figure
      else if(strncmp(command, "End", 3) == 0)
      {
         printf("Found a End command\n");
         //strncpy(array_figure[count].name, command, LINE_LEN);
         //printf("%s\n", array_figure[count].name);

         count2++;
         count = 0;
      }

      //organizes and prints coordinates to console
      else if(strncmp(command, "printFigure", 11) == 0)
      {
         //printf("Print Figure %s\n", name); **UNCOMMENT**
         while(strncmp(array_figure[printFigureCount].name, name, LINE_LEN) != 0 &&
            printFigureCount < FIGURE_MAX)
            printFigureCount++;

         if(printFigureCount < FIGURE_MAX)
         {
            for(i=0; i< POINTS_MAX; ++i)
            {
               if(array_figure[printFigureCount].Coord[i].xcoor != fup_value &&
                  array_figure[printFigureCount].Coord[i].ycoor != fup_value)
               {
                  //converts values to int for printing
                  int intConvertX = (int) array_figure[printFigureCount].Coord[i].xcoor;
                  int intConvertY = (int) array_figure[printFigureCount].Coord[i].ycoor;
                  //printf("%d %d\n", intConvertX, intConvertY); **UNCOMMENT**
               }
            }
         }
      }

      else if(strncmp(command, "translate", 9) == 0)
      {
         printf("Found a Translate command\n");
         //translate++;
      }
      /*else if(strncmp(command, "clearScreen", 11) == 0)
      {
      sscanf(line, "%s%s", command, clear);
      printf("%s\n", clear);

      }*/
      else if(strncmp(command, "child", 5) == 0)
      {
         sscanf(line, "%s%s", command, clear);
         printf("Found a child command\n");
         //printf("\t\t\tsending child\n");

         fprintf(pipe, "%s", &line[5]);
         printf("passed fprintf\n");

         if(strncmp(clear, "clearScreen", 11) == 0)
         {
            printf("%s\n", clear);
            fprintf(pipe, "%s", &clear[11]);
            break;
         }

         //printf("\t\t\tdone -- sending child\n");
      }
      else if(strncmp(command, "#", 1) == 0)
      {
         printf("Found a # command\n");
         //printf("%s", line); **COMMENT OUT**
      }
   }

If you take a notice whenever it says "clearScreen" it will appear in the text file as "child clearScreen" thus the if(strncmp(clear, "clearScreen", 11) == 0). I have it break afterwards, but I would like to make it call another function to reinitialize an array so i don't have to leave the function.

Answer 1

Depends on what you mean by "initialize".

If you have your struct array declared as

struct figure array_figure[19];

and you simply want to set all the values of the elements back to their defaults, then you can pass the array to a function and modifiy it inside the function (technically you are passing the pointer to the first element). A signature for such a function could look something like this:

void modify(struct figure *array_of_structs, unsigned int length_of_array)

and call it as follows:

modify(array_figure, 19); // if 19 is the length, that is

If you want a completely new array, then you must allocate a new one as suggested by Jonathan Cruz.

Answer 2

To initialize you use malloc to allocate the memory needed. malloc returns a pointer so you can put that in a function. If you want reinitialize you can free the struct and do it over again.

Something like:

typedef struct mystruct {
    // ...
}MyStruct;

MyStruct* getMyStruct() {
    return (MyStruct*) malloc(sizeof(MyStruct));
}

Check those links, that might help.

http://www.cplusplus.com/reference/clibrary/cstdlib/malloc/

http://www.cplusplus.com/reference/clibrary/cstring/memset/