请在此代码中增加答题窗口：int main() { welcome(); int i, j, k, answer, result; int num1, num2; char op; int score = 0; // 调用欢迎界面函数 welcome(); // 等待用户按下任意键继续 system("pause"); // 清屏 system("cls"); // 生成随机数种子 srand((unsigned)time(NULL)); // 循环出题 for (i = 0; i < 10; i++) { // 生成两个随机数和一个随机运算符 num1 = rand() % 100 + 1; num2 = rand() % 100 + 1; k = rand() % 4; switch (k) { case 0: op = '+'; result = num1 + num2; break; case 1: op = '-'; result = num1 - num2; break; case 2: op = '*'; result = num1 * num2; break; case 3: // 如果除数为0，则重新生成题目 if (num2 == 0) { i--; continue; } // 如果不能整除，则重新生成除数 if (num1 % num2 != 0) { i--; continue; } op = '/'; result = num1 / num2; break; } // 输出题目 printf("第%d题：%d %c %d = ", i + 1, num1, op, num2); // 等待用户输入答案 scanf("%d", &answer); // 判断答案是否正确 if (answer == result) { printf("回答正确！\n"); score += 10; } else { printf("回答错误！\n"); } }

可以在代码中增加以下答题窗口的代码：

#include <windows.h>

// 定义答题窗口的大小和位置
#define BOX_WIDTH 60
#define BOX_HEIGHT 10
#define BOX_LEFT ((GetSystemMetrics(SM_CXSCREEN) - BOX_WIDTH) / 2)
#define BOX_TOP ((GetSystemMetrics(SM_CYSCREEN) - BOX_HEIGHT) / 2)

// 显示答题窗口
void showAnswerWindow() {
    // 获取窗口句柄和设备上下文
    HWND hwnd = GetForegroundWindow();
    HDC hdc = GetDC(hwnd);

    // 创建画刷，填充背景色为白色
    HBRUSH hbrush = CreateSolidBrush(RGB(255, 255, 255));
    RECT rect = { BOX_LEFT, BOX_TOP, BOX_LEFT + BOX_WIDTH, BOX_TOP + BOX_HEIGHT };
    FillRect(hdc, &rect, hbrush);

    // 绘制答题框和文本框
    HBRUSH hbrush2 = CreateSolidBrush(RGB(220, 220, 220));
    RECT rect2 = { BOX_LEFT + 10, BOX_TOP + 10, BOX_LEFT + BOX_WIDTH - 10, BOX_TOP + BOX_HEIGHT - 10 };
    FillRect(hdc, &rect2, hbrush2);
    MoveToEx(hdc, BOX_LEFT + 10, BOX_TOP + 30, NULL);
    LineTo(hdc, BOX_LEFT + BOX_WIDTH - 10, BOX_TOP + 30);
    TextOut(hdc, BOX_LEFT + 20, BOX_TOP + 20, "请在下方输入答案：", strlen("请在下方输入答案："));

    // 释放资源
    DeleteObject(hbrush);
    DeleteObject(hbrush2);
    ReleaseDC(hwnd, hdc);
}

// 获取用户输入的答案
int getAnswerFromUser() {
    int answer;
    // 显示答题窗口
    showAnswerWindow();
    // 获取用户输入
    HWND hwnd = GetForegroundWindow();
    HDC hdc = GetDC(hwnd);
    char str[100];
    scanf("%s", str);
    answer = atoi(str);
    // 清空输入缓冲区
    fflush(stdin);
    // 释放资源
    ReleaseDC(hwnd, hdc);
    return answer;
}

然后在主函数中使用`getAnswerFromUser()`函数来获取用户输入的答案：

// 循环出题
for (i = 0; i < 10; i++) {
    // 生成两个随机数和一个随机运算符
    num1 = rand() % 100 + 1;
    num2 = rand() % 100 + 1;
    k = rand() % 4;
    switch (k) {
        case 0:
            op = '+';
            result = num1 + num2;
            break;
        case 1:
            op = '-';
            result = num1 - num2;
            break;
        case 2:
            op = '*';
            result = num1 * num2;
            break;
        case 3:
            // 如果除数为0，则重新生成题目
            if (num2 == 0) {
                i--;
                continue;
            }
            // 如果不能整除，则重新生成除数
            if (num1 % num2 != 0) {
                i--;
                continue;
            }
            op = '/';
            result = num1 / num2;
            break;
    }

    // 输出题目
    printf("第%d题：%d %c %d = ", i + 1, num1, op, num2);

    // 等待用户输入答案
    int answer = getAnswerFromUser();

    // 判断答案是否正确
    if (answer == result) {
        printf("回答正确！\n");
        score += 10;
    } else {
        printf("回答错误！\n");
    }
}