Re: [問題]C++ 九九乘法表 如何用if來寫呢??

[yauhh (喲)]

※ 引述《lianchiamin (lianchiamin)》之銘言：
: 這是我跟我同學想到的問題
: 現在有想到用do while寫
: 但卻不知道如何用if來寫

記得國小的墊板嗎?

#include <iomanip>

enum Major {row, col};

void multiple_table(enum Major m, int fromRow, int fromCol,
                                  int toRow,   int toCol);

int main(int argc, char *argv[]) {
    multiple_table(col, 2, 1, 5, 9);
    cout << endl;
    multiple_table(col, 6, 1, 9, 9);
    system("pause");
    return EXIT_SUCCESS;
}

void multiple_table(enum Major m, int fromRow, int fromCol,
int toRow, int toCol) {
    if (m == col) {
        if (fromCol >= toCol) {
            if (fromRow >= toRow) {
                cout << fromRow << " * " << fromCol << " = "
                     << setw(2) << (fromRow * fromCol) << endl;
                return;
            } else {
                cout << fromRow << " * " << fromCol << " = "
                     << setw(2) << (fromRow * fromCol) << "  ";
                multiple_table(col, fromRow+1, fromCol, toRow, toCol);
            }
        } else {
            multiple_table(col, fromRow, fromCol, toRow, fromCol);
            multiple_table(col, fromRow, fromCol+1, toRow, toCol);
        }
    } else /* if (m == row) */ {
        if (fromRow >= toRow) {
            if (fromCol >= toCol) {
                cout << fromRow << " * " << fromCol << " = "
                     << setw(2) << (fromRow * fromCol) << endl;
                return;
            } else {
                cout << fromRow << " * " << fromCol << " = "
                     << setw(2) << (fromRow * fromCol) << "  ";
                multiple_table(row, fromRow, fromCol+1, toRow, toCol);
            }
        } else {
            multiple_table(row, fromRow, fromCol, fromRow, toCol);
            multiple_table(row, fromRow+1, fromCol, toRow, toCol);
        }
    }
}

輸出為:
----------------------------------------------
2 * 1 =  2  3 * 1 =  3  4 * 1 =  4  5 * 1 =  5
2 * 2 =  4  3 * 2 =  6  4 * 2 =  8  5 * 2 = 10
2 * 3 =  6  3 * 3 =  9  4 * 3 = 12  5 * 3 = 15
2 * 4 =  8  3 * 4 = 12  4 * 4 = 16  5 * 4 = 20
2 * 5 = 10  3 * 5 = 15  4 * 5 = 20  5 * 5 = 25
2 * 6 = 12  3 * 6 = 18  4 * 6 = 24  5 * 6 = 30
2 * 7 = 14  3 * 7 = 21  4 * 7 = 28  5 * 7 = 35
2 * 8 = 16  3 * 8 = 24  4 * 8 = 32  5 * 8 = 40
2 * 9 = 18  3 * 9 = 27  4 * 9 = 36  5 * 9 = 45

6 * 1 =  6  7 * 1 =  7  8 * 1 =  8  9 * 1 =  9
6 * 2 = 12  7 * 2 = 14  8 * 2 = 16  9 * 2 = 18
6 * 3 = 18  7 * 3 = 21  8 * 3 = 24  9 * 3 = 27
6 * 4 = 24  7 * 4 = 28  8 * 4 = 32  9 * 4 = 36
6 * 5 = 30  7 * 5 = 35  8 * 5 = 40  9 * 5 = 45
6 * 6 = 36  7 * 6 = 42  8 * 6 = 48  9 * 6 = 54
6 * 7 = 42  7 * 7 = 49  8 * 7 = 56  9 * 7 = 63
6 * 8 = 48  7 * 8 = 56  8 * 8 = 64  9 * 8 = 72
6 * 9 = 54  7 * 9 = 63  8 * 9 = 72  9 * 9 = 81
請按任意鍵繼續 . . .
----------------------------------------------


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