Question

我正在编写带开关功能的代码。我希望我的默认代码打印“错误”并使程序停止运行。我应该在默认结束时添加return 1;吗？

如果是的话，这是对的吗？

switch (course3)
{
    case 'I':
        course3 = 5;
        grade3 = grade3 + 2;
        break;
    case 'O': 
        course3 = 4;
        grade3 = grade3 - 3;
        break;
    case 'A': 
        course3 = 3;
        grade3 = grade3 + 8;
        break;
    case 'D': 
        course3 = 2;
        grade3 = grade3*1.06;
        break;
    case 'L': 
        course3 = 1;
        grade3 = 10 * sqrt(grade3);
        break;
    default:
        printf("Error\n");
        return 1;
}

Answer 1

假设这个代码块驻留在select t.id, t.title, r.id, r.body from forum_responses r inner join forum_topics t on (r.forum_topic_id = t.id) order by r.id desc; +----+--------------+----+----------------------------------+ | id | title | id | body | +----+--------------+----+----------------------------------+ | 17 | New Topic | 69 | yes | | 19 | Test Topic 1 | 68 | This is a test | | 17 | New Topic | 64 | hey yo | | 19 | Test Topic 1 | 63 | Test Topic Starter | | 18 | Test Topic | 62 | Test. | | 18 | Test Topic | 61 | Test | | 17 | New Topic | 60 | Another test response. | | 17 | New Topic | 59 | Test response. | | 17 | New Topic | 54 | What should this topic be about? | +----+--------------+----+----------------------------------+函数中，那么使用select t.id, t.title, r.id, r.body from forum_responses r inner join forum_topics t on (r.forum_topic_id = t.id) group by t.id order by r.id desc; +----+--------------+----+----------------------------------+ | id | title | id | body | +----+--------------+----+----------------------------------+ | 19 | Test Topic 1 | 63 | Test Topic Starter | | 18 | Test Topic | 61 | Test | | 17 | New Topic | 54 | What should this topic be about? | +----+--------------+----+----------------------------------+是的，将完成此操作，因为从main返回相当于调用return 1;。

如果此块不在main中，则exit语句将返回到调用函数。在这种情况下，您需要明确调用main以获得相同的结果。

返回定义（开关）

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