structs.c

structs.c

contents ::

  insertion-int.c
  insertion-sort.c
  strings.c
  structs.c

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

#define OCEAN_MAX 10000 //41981

struct ocean_datum {
  int x;  /* grid ref east-west  */
  int y;  /* grid ref west-south */
  double conc;  /* concentration of O2 in mL/L found at grid-ref (x,y) */
};

void ocean_datum_print(struct ocean_datum *o);

void insertion_sort(struct ocean_datum *a, int n){
  struct ocean_datum guide;
  int i;
  struct ocean_datum value;
  int j;

  guide.x=0;
  guide.y=0;
  guide.conc=0;

  value.x=0;
  value.y=0;
  value.conc=0;

  for (i=0; i<n; i++){
    value = a[i];

    if(a[i].conc < guide.conc){
      for(j=i-1; j >=0 && a[j].conc > value.conc; j--){
         a[j+1]=a[j];
      }
      a[j+1]=value;
    }
    if (value.conc > guide.conc) guide=value;
/*      printf("Value: "); */
/*      ocean_datum_print(&value); */
/*      printf("Guide: "); */
/*      ocean_datum_print(&guide); */
  }
}

void ocean_datum_print(struct ocean_datum *o){
  /* We need to reference the struct ocean_datum pointer to print it out,
     which is why we write (*o).x rather than o.x. Unfortunately, *o.x
     doeasn't work, since the "." operator has a higher precedence than the
     deference.
     o->x is shorthand for (*o).x and is a very common idiom.
  */
  printf("o: (%d, %d, %.4f)\n", (*o).x, o->y, o->conc);
}

main(){
  clock_t c,d;
  struct ocean_datum my_datum[OCEAN_MAX];
  int num_items=0;
  int i;

  while(num_items < OCEAN_MAX && 3 == scanf("%d %d %lg",
                                                 &my_datum[num_items].x,
                                                 &my_datum[num_items].y,
                                                 &my_datum[num_items].conc)){
    num_items++;
  }

  c=clock();
  insertion_sort(my_datum, num_items);
  d=clock();

  // for(i=0; i<num_items; i++)
  // ocean_datum_print(&my_datum[i]);
  fprintf(stderr,"%d\t%f\n",num_items,(d-c)/(double)CLOCKS_PER_SEC);

  return EXIT_SUCCESS;
}

James Little