単連結リストの整列 #108 足りない機能の追加

たぶん使うであろう機能の不足を追加。

grade.h

...snip

/*
returns the letter representing this grade.
*/
char grade_toletter(grade_t g);

#endif /* GRADE_H_INCLUDED */

grade.c

...snip
struct tag_grade {
    enum {GRADE_VAL_A = 5, GRADE_VAL_B = 4, GRADE_VAL_C = 3, GRADE_VAL_D = 2, GRADE_VAL_F = 1} grade;
    char cgrade;
};

static struct tag_grade grades[] = {{GRADE_VAL_A, 'A'}, {GRADE_VAL_B, 'B'}, {GRADE_VAL_C, 'C'}, {GRADE_VAL_D, 'D'}, {GRADE_VAL_F, 'F'}};
...snip

char grade_toletter(grade_t g)
{
    return g->cgrade;
}

評点の文字表現を返す。