Tabulkove makro v C

c_tabular_macro.c

/******************************************************************************/
/*                              TABULKOVA MAKRA                               */
/******************************************************************************/
/**
 * tak jak nam je ukazoval dr. Peringer 2. 5. 2023 na prednasce
 * pry to objevil nekde v kodu GCC
*/

#undef ROW  /* to be defined later */

/* Name, Surname, Age, City */
#define TABLE                                            \
    ROW("Vit",    "Pavlik",   20, Brno)                  \
    ROW("Prokop", "Buben",    30, Praha)                 \
    ROW("Blanka", "Protrhla", 19, JindrichuvHradec)

/**
 * V cem je figl? Krome retezcu nebo cisel muzu mit v tabulce ruzne veci:
 * ukazatele, ukazatele na funkce a jine kulisarny.
 * 
 * Takto muzu souvisejici polozky pridat jen na jednom miste a vubec needitovat
 * kod na mistech kde se to pouziva.
 * 
 * Vzdycky jen nadefinuju makro ROW pro vyber prislusneho sloupce.
*/

/******************************************************************************/
/* KOD: kdyz pridam do tabulky nejake polozky tak ho vubec neupravuji!        */
/******************************************************************************/

#include <stdio.h>

/* enum of city identifiers */
#define ROW(name, surname, age, city) city,
enum cities {
    TABLE
    LENGTH  /* sentinel value: number of items */
};
#undef ROW

int main(void) {

    /* array of names */
    #define ROW(name, surname, age, city) name,
    const char *names[] = {TABLE};
    #undef ROW

    /* array of ages*/
    #define ROW(name, surname, age, city) age,
    int ages[] = {TABLE};
    #undef ROW

    for (int i = 0; i < LENGTH; i++) {
        printf("%s is %d years old. (city = %d) \n", names[i], ages[i], i);
    }
}