综合挑战Final Challenge

恭喜你学完了 Level 0 的所有知识！现在来做一个综合挑战，把学到的东西全用上。Congratulations on finishing all of Level 0! Now let's do a final challenge that uses everything you've learned.

8.1 要求8.1 Requirements

1. 使用循环（for 或 while 都行）Use loops (for or while — either works)
2. 每行显示一组乘法，格式像这样：3 x 4 = 12Each line shows one multiplication, like this: 3 x 4 = 12
3. Brain 屏幕行数有限，显示满了要清屏重来The Brain screen has limited lines, so clear the screen when it's full

这次不给框架代码 — 请从空白的 main() 开始，自己写出来。This time there's no starter code — start from an empty main() and write it yourself.

8.2 参考思路8.2 Hints

如果你卡住了，可以一步步打开下面的提示。每次只打开一个，试试能不能继续。If you get stuck, open the hints below one at a time. Only open one at a time and try to continue on your own.

for (int a = 1; a <= 5; a++) {
    for (int b = 1; b <= 5; b++) {
        // a x b = ?
    }
}

int row = 1;

// 每显示一行：
Brain.Screen.setCursor(row, 1);
Brain.Screen.print("...");
row++;  // 下一行

if (row > 10) {
    wait(2000, msec);           // 让用户看 2 秒
    Brain.Screen.clearScreen(); // 清屏
    row = 1;                    // 重新从第 1 行开始
}

8.3 参考答案8.3 Reference Answer

自己写完后再看答案！对比一下你的写法和参考答案有什么不同。只要能正确显示乘法表，你的写法就是对的。Try writing it yourself before checking the answer! Compare your approach with the reference. As long as your multiplication table displays correctly, your code is correct.

int main() {
    int row = 1;

    for (int a = 1; a <= 5; a++) {
        for (int b = 1; b <= 5; b++) {
            // 屏幕满了就清屏
            if (row > 10) {
                wait(2000, msec);
                Brain.Screen.clearScreen();
                row = 1;
            }

            Brain.Screen.setCursor(row, 1);
            Brain.Screen.print("%d x %d = %d", a, b, a * b);
            row++;

            wait(300, msec);
        }
    }

    return 0;
}

int main() {
    int row = 1;

    for (int a = 1; a <= 5; a++) {
        for (int b = 1; b <= 5; b++) {
            // 屏幕满了就清屏
            if (row > 10) {
                wait(2000, msec);
                Brain.Screen.clearScreen();
                row = 1;
            }

            Brain.Screen.setCursor(row, 1);
            Brain.Screen.print("%d x %d = %d", a, b, a * b);
            row++;

            wait(300, msec);
        }
    }

    return 0;
}

void opcontrol() {
    int row = 1;

    for (int a = 1; a <= 5; a++) {
        for (int b = 1; b <= 5; b++) {
            // 屏幕满了就清屏
            if (row > 7) {
                pros::delay(2000);
                pros::lcd::clear();
                row = 1;
            }

            std::string line = std::to_string(a) + " x "
                + std::to_string(b) + " = "
                + std::to_string(a * b);
            pros::lcd::set_text(row, line);
            row++;

            pros::delay(300);
        }
    }
}

8.4 拓展思考8.4 Extra Challenges

如果你做完了基础挑战，可以试试这些升级版：If you've completed the basic challenge, try these upgrades:

• 升级 1：改成 1×1 到 9×9 的完整乘法表Upgrade 1: Make it a full 1×1 to 9×9 multiplication table
• 升级 2：不重复 — 只显示 a ≤ b 的情况（比如显示 2×3 但不显示 3×2）Upgrade 2: No duplicates — only show cases where a ≤ b (e.g. show 2×3 but not 3×2)
• 升级 3：用 if 判断，如果结果是两位数以上就多空一格对齐Upgrade 3: Use if to add an extra space when the result has two or more digits, for alignment

8.5 动手预测8.5 Predict the Output

最后一道思考题：看下面这个嵌套循环，一共会打印几行？One last brain teaser: look at the nested loop below — how many lines will it print in total?

for (int i = 1; i <= 3; i++) {
    for (int j = 1; j <= 4; j++) {
        // 打印一行
    }
}