# include < stdio . h ># include < conio . h > main ( ) { int i , j , k ; printf ( "----------- 구 구 단 ------------------------\ n \ n "); for ( k = 11 ; k <= 16 ; k = k + 5 ) { for ( i = 1 ; i <= 9 ; i ++){ for ( j = k ; j < k + 5 ; j ++){ printf ( "% 2 d *% 2 d =% 3 d ", j , i , i * j ) ; } printf ( "\ n "); } printf ( " - - - - - - - - - - - - - - - - - - - - - - - ------------------------\ n "); }}