Answer T30

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

typedef struct
{
  int x, y;
} Point;

void printPoint( Point *p )
{
  printf("(%d, %d) ", p->x, p->y );
}

Point *newPoint()
{
  Point *p = (Point *)malloc( sizeof( Point ) );
  p->x=0;
  p->y=0;
  return p;
}

void setPoint( Point *p, int x, int y )
{
  p->x = x; p->y = y;
}

typedef struct
{
  int red, green, blue;
} Color;

Color *newColor()
{
  Color *c = (Color *)malloc( sizeof( Color ) );
  c->red=0;
  c->green=0;
  c->blue=0;
  return c;
}

/* function to set a Color */
void setColor( Color *c, int r, int g, int b )
{
  if ( r<0 || r>255 ) r = 0;
  if ( g<0 || g>255 ) g = 0;
  if ( b<0 || b>255 ) b = 0;

  c->red   = r;
  c->green = g;
  c->blue  = b;
}

void printColor( Color *c )
{
  printf("%3d red, %3d grn, %3d blu", c->red, c->green, c->blue );
}

typedef struct
{
  Point *p0, *p1, *p2;
  Color *color;
} TriangleMod;

void printTriangleMod( TriangleMod *t )
{
  printf("Points: ");
  printPoint( t->p0 ); printPoint( t->p1 ); printPoint( t->p2 );
  printf("  Color: ");
  printColor( t->color );
  printf("\n");
}

TriangleMod *newTriangleMod()
{
  TriangleMod *tm;
  tm = (TriangleMod *)malloc( sizeof( TriangleMod ) );
  tm->p0 = newPoint();
  tm->p1 = newPoint();
  tm->p2 = newPoint();
  tm->color = newColor();

  return tm;
}

void freeTriangleMod( TriangleMod *t )
{
  free( t->color);
  free( t->p0);
  free( t->p1);
  free( t->p2);
  free( t );
}

void setTriangleModPoint( TriangleMod *tri, int num, int x, int y)
{
  if ( num==0 ) setPoint( tri->p0, x, y );
  if ( num==1 ) setPoint( tri->p1, x, y );
  if ( num==2 ) setPoint( tri->p2, x, y );
}

void setTriangleModColor( TriangleMod *tri, int r, int g, int b)
{
  setColor( tri->color, r, g, b );
}

typedef struct
{
  int length;
  TriangleMod **array;
} TriCollection;

TriCollection *newTriCollection( int len )
{
  int j;
  
  TriCollection *coll = (TriCollection *)malloc( sizeof(TriCollection) );
  coll->length = len;
  coll->array  = (TriangleMod**)malloc( len*sizeof( TriangleMod* ) );
  for ( j=0; j<len; j++ )
    coll->array[j] = NULL;
    
  return coll;
}

void freeTriCollection( TriCollection *col )
{
  int j;
  for ( j=0; j<col->length; j++ )
    if ( col->array[j] ) freeTriangleMod( col->array[j] );

  free( col->array );
  free( col );
}

int main()
{
  const int length = 8;
  int j;

  TriCollection *triarray = newTriCollection( 8 );

  /* Create several array elements here */
  triarray->array[0] = newTriangleMod();
  setTriangleModPoint( triarray->array[0], 0, 245, 148 );
  setTriangleModPoint( triarray->array[0], 1, -97,  32 );
  setTriangleModPoint( triarray->array[0], 2, 12, -34 );
  setTriangleModColor( triarray->array[0], 200, 160, 100);

  triarray->array[3] = newTriangleMod();
  setTriangleModPoint( triarray->array[3], 0, 0, 0 );
  setTriangleModPoint( triarray->array[3], 1, 100, 0 );
  setTriangleModPoint( triarray->array[3], 2, 100, 100 );
  setTriangleModColor( triarray->array[3], 0, 150, 150);

  triarray->array[5] = newTriangleMod();
  setTriangleModPoint( triarray->array[5], 0, 99, 65 );
  setTriangleModPoint( triarray->array[5], 1, 123, 300 );
  setTriangleModPoint( triarray->array[5], 2, 134, -12 );
  setTriangleModColor( triarray->array[5], 100, 250, 200 );

  /* Print out the array here. Print "null" for empty cells. */
  for ( j=0; j<length; j++ )
  {
    printf("%d: ", j );
    if ( !triarray->array[j] )
      printf("null\n");
    else
      printTriangleMod( triarray->array[j] );
  }

  /* Deallocate memory */
  freeTriCollection( triarray );
  
}