Re: [問題] 九九乘法表不用迴圈是叫我直接從1列到81?

看板C_and_CPP (C/C++)作者holydc (のヮの)時間6年前 (2018/07/16 22:48)推噓2(2推 0噓 3→)

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: 九九乘法表用兩個或一個迴圈來做我都會 : 但不用迴圈叫我列九九乘法表是哪招？ : 難道是要我直接從1*1列到9*9嗎？ : 還是其實有妙招？ : 說實在我真想不到不用迴圈就能簡單列出九九乘法表的方法了我覺得這題要求用 C 真的比較困難，C++ 的話可以輕鬆很多大概像這樣 https://ideone.com/Yb0TqG #include <iomanip> #include <iostream> template<int...> struct IntegerSequence { }; template<int n, class = IntegerSequence<>, bool = n == 0> struct MakeIntegerSequenceImpl; template<int n, int... i> struct MakeIntegerSequenceImpl<n, IntegerSequence<i...>, true> { typedef IntegerSequence<i...> type; }; template<int n, int... i> struct MakeIntegerSequenceImpl<n, IntegerSequence<i...>, false> { typedef typename MakeIntegerSequenceImpl< n - 1, IntegerSequence<n - 1, i...>>::type type; }; template<int n> using MakeIntegerSequence = typename MakeIntegerSequenceImpl<n>::type; template<int n> struct MultiplicationTableCell { static constexpr int value = ((n / 9) + 1) * ((n % 9) + 1); }; template<class> struct MultiplicationTableImpl; template<int... n> struct MultiplicationTableImpl<IntegerSequence<n...>> { static const int value[]; }; template<int... n> const int MultiplicationTableImpl<IntegerSequence<n...>>::value[] = { MultiplicationTableCell<n>::value... }; struct MultiplicationTable : MultiplicationTableImpl<MakeIntegerSequence<81>> { static void print_twoLoops() { for (int i = 0; i < 9; ++i) { for (int j = 0; j < 9; ++j) { std::cout << std::setw(2) << value[(i * 9) + j] << ','; } std::cout << std::endl; } } static void print_oneLoop() { for (int i = 0; i < 81; ++i) { std::cout << std::setw(2) << value[i] << ','; if ((i % 9) == 8) { std::cout << std::endl; } } } static void print_noLoop_twoArgs(int i = 0, int j = 0) { if (i == 9) { return; } if (j == 9) { std::cout << std::endl; return print_noLoop_twoArgs(i + 1, 0); } std::cout << std::setw(2) << value[(i * 9) + j] << ','; print_noLoop_twoArgs(i, j + 1); } static void print_noLoop_oneArg(int i = 0) { if (i == 81) { return; } std::cout << std::setw(2) << value[i] << ','; if ((i % 9) == 8) { std::cout << std::endl; } print_noLoop_oneArg(i + 1); } }; int main() { std::cout << "Use 'two' for loops:" << std::endl; MultiplicationTable::print_twoLoops(); std::cout << std::endl; std::cout << "Use 'only one' for loop:" << std::endl; MultiplicationTable::print_oneLoop(); std::cout << std::endl; std::cout << "Use 'no loops' (two arguments):" << std::endl; MultiplicationTable::print_noLoop_twoArgs(); std::cout << std::endl; std::cout << "Use 'no loops' (one argument):" << std::endl; MultiplicationTable::print_noLoop_oneArg(); return 0; } -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 114.43.180.55 ※ 文章網址: https://www.ptt.cc/bbs/C_and_CPP/M.1531752496.A.59E.html