Question

我正在尝试制作一个模板，这是我的课堂作业。我在do while循环中使用了switch语句，条件是如果输入变量不等于16，则应终止程序

我已经在每种情况下都使用了中断声明，但是它不起作用

#include <iostream>

using namespace std;

int main()
{
    int op;

    cout << "Please enter choice between 1 to 15 For Different Operations "
         << endl;

    cout << "1. Create List(create a new list(presumably empty))" << endl;
    cout << "2. Insertion" << endl;
    cout << "3. Deletion" << endl;
    cout << "4. Update(replace the element)" << endl;
    cout << "5. Start" << endl;
    cout << "6. Next" << endl;
    cout << "7. Back" << endl;
    cout << "8. Tail" << endl;
    cout << "9. Find" << endl;
    cout << "10. Copy" << endl;
    cout << "11. Get(display current index and element)" << endl;
    cout << "12. Size / length" << endl;
    cout << "13. Display list" << endl;
    cout << "14. De - allocate list" << endl;
    cout << "15. Exit" << endl;

    cin >> op;
    do {
        switch (op) {
        case 1:
            cout << "Creating the List" << endl;
            break;
        case 2:
            cout << "inserting... " << endl;
            break;
        case 3:
            cout << "Deleting... " << endl;
            break;
        case 4:
            cout << "updating... " << endl;
            break;
        case 5:
            cout << "starting... " << endl;
            break;
        case 6:
            cout << "next... " << endl;
            break;
        case 7:
            cout << "back... " << endl;
            break;
        case 8:
            cout << "Tail... " << endl;
            break;
        case 9:
            cout << "Find... " << endl;
            break;
        case 10:
            cout << "Copying... " << endl;
            break;
        case 11:
            cout << "Getting... " << endl;
            break;
        case 12:
            cout << "Size... " << endl;
            break;
        case 13:
            cout << "Display... " << endl;
            break;
        case 14:
            cout << "Deallocate... " << endl;
            break;
        case 15:
            terminate;
            break;
        default:
            cout << "Please enter the correct choice " << endl;
            break;
        }
    } while (op != 16);
    return 0;
}

我希望用户做出的每个选择中都有cout输出，然后停止输入

Answer 1

使用原始代码

   cin >> op;
   do {
     switch (op)

因此您从循环外的cin处读取，再也不会再次读取，因此重新排序以便每次循环读取时都会再次询问您所需的操作

   do {
     cin >> op;
     switch (op)

另外请注意，break不会中断循环，而只是从开关中断。在不中断的情况下，下一种情况的指令也将在开关中执行。

如果要在某些情况下从循环中中断，则需要在switch语句之外添加一个中断，如果应该退出循环，则可以使用变量来“记住”。

但是，由于键入指令中存在退出条件，为什么不退出循环

} while (op != 15);

这似乎很合理，因为

cout << "15. Exit" << endl;

行。

为什么我的程序连续运行而不停止？

1 个答案: