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

void function0(void) { printf("function 0\n"); }
void function1(void) { printf("function 1\n"); }
void function2(void) { printf("function 2\n"); }
typedef void (*VoidToVoid)(void);

int main(int argc, char *argv[]) {
    VoidToVoid functions[3] = {function0, function1, function2};
    if (argc != 2) {
        printf("one argument only\n");
        return EXIT_FAILURE;
    }

    unsigned char index = strtol(argv[1], NULL, 10);

    if (index > 2) {
        printf("argument must be between 0 and 2\n");
        return EXIT_FAILURE;
    }

    functions[index]();

    return EXIT_SUCCESS;
}