Radio

Radio is a special form of Checkbox. You can use it when you want the user to make an 'exclusive or' decision. Contrary to a simple Checkbox, which only outputs true or false, a Radio can Output more Options.

enum {EASY, HARD};
static int op = EASY;

    nk_layout_row_dynamic(ctx, 30, 2);
    if (nk_option_label(ctx, "easy", op == EASY)) op = EASY;
    if (nk_option_label(ctx, "hard", op == HARD)) op = HARD;