Question

初学者在这里。所以我编写了一个代码来提示用户输入两个不同的数字。 if语句表示如果数字是＆lt; = 0，它应该提示用户输入满足它的不同数字。但是，每次输入正数时，这个不正确的提示仍会出现。有点烦人。谁能让我走上正确的道路？

IActuator

Answer 1

你犯了一些错误。你把大小作为一个字符串，大小应该作为一个int，因为它是一个数字。字符串基本上是一个字符数组。

    Error   1    error: cannot find symbol
        android.support.v4.content.Loader.OnLoadCanceledListener
  symbol:   class OnLoadCanceledListener
  location: class Loader
    xxx\obj\Debug\android\src\mono\android\support\v4\content\Loader_OnLoadCanceledListenerImplementor.java 8   36  xxx
Error   6    error: cannot find symbol
        android.support.v4.view.MenuItemCompat.OnActionExpandListener
  symbol:   class OnActionExpandListener
  location: class MenuItemCompat
    xxx\obj\Debug\android\src\mono\android\support\v4\view\MenuItemCompat_OnActionExpandListenerImplementor.java    8   41  xxx
Error   7    error: cannot find symbol
        android.support.v4.view.OnApplyWindowInsetsListener
  symbol:   class OnApplyWindowInsetsListener
  location: package android.support.v4.view
    xxx\obj\Debug\android\src\mono\android\support\v4\view\OnApplyWindowInsetsListenerImplementor.java  8   26  xxx
Error   12   error: cannot find symbol
        android.support.v4.view.ViewPropertyAnimatorListener
  symbol:   class ViewPropertyAnimatorListener
  location: package android.support.v4.view
    xxx\obj\Debug\android\src\mono\android\support\v4\view\ViewPropertyAnimatorListenerImplementor.java 8   26  xxx
Error   13   error: cannot find symbol
        android.support.v4.view.ViewPropertyAnimatorUpdateListener
  symbol:   class ViewPropertyAnimatorUpdateListener
  location: package android.support.v4.view
    xxx\obj\Debug\android\src\mono\android\support\v4\view\ViewPropertyAnimatorUpdateListenerImplementor.java   8   26  xxx
Error   10   error: cannot find symbol
    private native android.support.v4.view.WindowInsetsCompat n_onApplyWindowInsets (android.view.View p0, android.support.v4.view.WindowInsetsCompat p1);
  symbol:   class WindowInsetsCompat
  location: package android.support.v4.view
    xxx\obj\Debug\android\src\mono\android\support\v4\view\OnApplyWindowInsetsListenerImplementor.java  32  128 xxx
Error   11   error: cannot find symbol
    private native android.support.v4.view.WindowInsetsCompat n_onApplyWindowInsets (android.view.View p0, android.support.v4.view.WindowInsetsCompat p1);
  symbol:   class WindowInsetsCompat
  location: package android.support.v4.view
    xxx\obj\Debug\android\src\mono\android\support\v4\view\OnApplyWindowInsetsListenerImplementor.java  32  40  xxx
Error   8    error: cannot find symbol
    public android.support.v4.view.WindowInsetsCompat onApplyWindowInsets (android.view.View p0, android.support.v4.view.WindowInsetsCompat p1)
  symbol:   class WindowInsetsCompat
  location: package android.support.v4.view
    xxx\obj\Debug\android\src\mono\android\support\v4\view\OnApplyWindowInsetsListenerImplementor.java  27  118 xxx
Error   9    error: cannot find symbol
    public android.support.v4.view.WindowInsetsCompat onApplyWindowInsets (android.view.View p0, android.support.v4.view.WindowInsetsCompat p1)
  symbol:   class WindowInsetsCompat
  location: package android.support.v4.view
    xxx\obj\Debug\android\src\mono\android\support\v4\view\OnApplyWindowInsetsListenerImplementor.java  27  32  xxx
Error   2    error: package android.support.v4.media.session.MediaSessionCompat does not exist
        android.support.v4.media.session.MediaSessionCompat.OnActiveChangeListener
    xxx\obj\Debug\android\src\mono\android\support\v4\media\session\MediaSessionCompat_OnActiveChangeListenerImplementor.java   8   54  xxx
Error   3    error: package android.support.v4.os.CancellationSignal does not exist
        android.support.v4.os.CancellationSignal.OnCancelListener
    xxx\obj\Debug\android\src\mono\android\support\v4\os\CancellationSignal_OnCancelListenerImplementor.java    8   43  xxx
Error   4    error: package android.support.v4.view.ActionProvider does not exist
        android.support.v4.view.ActionProvider.SubUiVisibilityListener
    xxx\obj\Debug\android\src\mono\android\support\v4\view\ActionProvider_SubUiVisibilityListenerImplementor.java   8   41  xxx
Error   5    error: package android.support.v4.view.ActionProvider does not exist
        android.support.v4.view.ActionProvider.VisibilityListener
    xxx\obj\Debug\android\src\mono\android\support\v4\view\ActionProvider_VisibilityListenerImplementor.java    8   41  xxx
Error   14   error: package android.support.v4.widget.SwipeRefreshLayout does not exist
        android.support.v4.widget.SwipeRefreshLayout.OnRefreshListener
    xxx\obj\Debug\android\src\mono\android\support\v4\widget\SwipeRefreshLayout_OnRefreshListenerImplementor.java   8   47  xxx

Answer 2

此

size = (char) str;

不如何将字符串转换为整数。我不完全确定你为什么会这么想。

这是将字符串转换为整数的最常用方法：

#include <stdlib.h>
size = atoi(str);

你在评论中提到它虽然没有用。我的猜测是因为你使用了没有原型的函数（即你没有包含stdlib.h），但是函数失败的原因有很多。

然而，正如您已经知道的那样（因为您稍后使用过），scanf可以直接接收整数值。您实际上不需要进行任何转换。

scanf("%d", &size);

C代码没有做它应该做的事情

2 个答案: