Storing both a double and a string in an array.

struct.c

#include <string.h>
#include <stdio.h>

#define STRING 1
#define DOUBLE 2

typedef struct _my_data 
{
  int    myDataType;
  double myDouble;
  char   myString[20];
} MyData;

int main ()
{
  MyData data[2];
  int count = 0;

  data[0].myDataType = STRING;
  strcpy(data[0].myString, "This is a String");
  
  data[1].myDataType = DOUBLE;
  data[1].myDouble   = 1.0;

  for ( count = 0; count < 2; count++ )
  {
    if ( data[count].myDataType == STRING )
    {
      printf("Its a string! %s\n", data[count].myString);
    }
    else if ( data[count].myDataType == DOUBLE )
    {
      printf("Its a double! %lf\n", data[count].myDouble);
    }
    else
    {
      printf("I don't know what kind of data that is.\n");
    }
  }
  
  return 0;
}

Interesting, whats this for?