Question

因此，我正在用C打井字游戏，但遇到一个问题，我要求用户按2来撤消他们的举动。每次轮到他们时，他们都可以撤消某步或继续进行操作。通过选择另一个键选择下一轮。

它应该如何工作，但是我遇到一个问题，如果用户输入字母字符，该程序只是反复循环通过说这不是数字来检查我的public void OnTrackableStateChanged(TrackableBehaviour.Status previousStatus, TrackableBehaviour.Status newStatus){ if (newStatus == TrackableBehaviour.Status.DETECTED || newStatus == TrackableBehaviour.Status.TRACKED || newStatus == TrackableBehaviour.Status.EXTENDED_TRACKED){ Debug.Log("Image Found"); } else{ Debug.Log("Image lost!"); } // StateManager stateManager = TrackerManager.Instance.GetStateManager(); IEnumerable<TrackableBehaviour> trackableBehaviours = stateManager.GetActiveTrackableBehaviours(); foreach (TrackableBehaviour trackableBehaviour in trackableBehaviours) { string scanName = trackableBehaviour.TrackableName; Transform.GetComponent<Text>().text = scanName; if(scanName == "scannedImage") { SceneManager.LoadScene("ScannedImageScene"); } else if(scanName == "otherImage") { SceneManager.LoadScene("OtherImageScene"); } } }函数。没有人知道如何使它停止执行此操作，只是说这不是一个数字，如果不循环程序的话？

这是我的代码：

GetHumanMove

Answer 1

scanf不会占用与您的格式不匹配的输入。它保留在输入流中。因此，当您输入字母时，它与您想要的数字%d不匹配，并停留在输入流中。

scanf("%d%c", &userInput, &term);

代替scanf，使用getline来消耗整个输入行会更简单。然后使用sscanf（函数的基于字符串的版本）或其他方法来解析结果。

char *line = NULL;
size_t len = 0;

while ((read = getline(&line, &len, stdin)) != -1) {
    // Do something with line

    int scanned = sscanf(line, "%d%c", &userInput);

    if (scanned == EOF || scanned != 2) {
        printf("Line failed to match\n");
    }
}

Answer 2

只需阅读手册页：

   The  format  string consists of a sequence of directives which describe
   how to process the sequence of input characters.  If  processing  of  a
   directive  fails,  no  further  input  is read, and scanf() returns.  A
   "failure" can be either of the following: input failure,  meaning  that
   input  characters  were  unavailable, or matching failure, meaning that
   the input was inappropriate (see below).

您不检查scanf()的返回值。因此，您始终尝试扫描与数字相同的非数字。

输入字母字符时，井字游戏用户输入会无限循环

2 个答案: