SimpleDataTable

#include <stdio.h>
#include <windows.h> // Windows sleep

#define TABLE_SIZE 3

typedef enum {TYPE_INT, TYPE_LONG, TYPE_CHAR} dataType;

typedef struct {
    void *data;
    dataType type;
} dataTable;

// Global for simplicity
static dataTable table[TABLE_SIZE];
static int var1 = 10;
static long var2 = 20;
static char var3 = 30;

// ===================================================================

void checkType(void *data, dataType type)
{
    if (type == TYPE_INT)
        printf("integer: %d\n", *((int *) data));
    else if (type == TYPE_LONG)
        printf("long: %ld\n", *((long *) data));
    else if (type == TYPE_CHAR)
        printf("char: %d\n", *((char *) data));
}

// "Main task"
void mainTask()
{
    var1 += 1;
    var2 += 1;
    var3 += 1;
}

// "Task"
void task()
{
    int i;
    printf("== Task ==\n");

    for (i = 0; i < TABLE_SIZE; ++i)
        checkType(table[i].data, table[i].type);
}

// Task with moving pointer
void ptrTask()
{
    static dataTable *current = table;

    printf("== Task with moving pointer ==\n");

    checkType(current->data, current->type);

    if (current == &table[TABLE_SIZE - 1])
        current = table;
    else
        ++current;
}

int main(int argc, char **argv)
{
    // Init
    table[0].data = &var1;
    table[0].type = TYPE_INT;

    table[1].data = &var2;
    table[1].type = TYPE_LONG;

    table[2].data = &var3;
    table[2].type = TYPE_CHAR;

    // Task
    while(1) {
        task();
        ptrTask();
        Sleep(500); // Windows sleep
        mainTask();
        Sleep(500); // Windows sleep
    }

    return 0;
}