Rest of the two digit numbers i . e . , 21 to 99
else { int i = * num - '0' ; printf ( " % s ▁ " , i ? tens_multiple [ i ] : " " ) ; ++ num ; if ( * num != '0' ) printf ( " % s ▁ " , single_digits [ * num - '0' ] ) ; } } ++ num ; } }