is_pressed.c

#include<stdio.h>

#define BUTTON1 1
#define BUTTON2 3
#define BUTTON3 6
#define BUTTON4 12

/* button, value */
#define IS_PRESSED(x, y) (y >> 4 == x)

int
main()
{
    int values[]={25, 29, 55, 56, 106, 109, 194, 195, 0};
    int i;

    for(i=0; values[i]!=0; i++)
    {
        printf("is pressed %d? %d\n", BUTTON1, IS_PRESSED(BUTTON1, values[i]));
    }

    return 0;
}