C++ 错误：'if' 之前的预期不合格 ID
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error: expected unqualified-id before 'if'
提问by mwcz
I've googled this error until I'm blue in the face, but haven't been able to relate any of the results to my code. This error seems to be caused, usually, but misplaced or missing braces, parents, etc.
我一直在用谷歌搜索这个错误，直到我脸色发青，但无法将任何结果与我的代码相关联。这个错误似乎通常是由错位或丢失的括号、父项等引起的。
It's also been a long time since I wrote any C++, so there could be some obvious, foolish thing that I'm missing.
我也已经很久没有写过任何 C++ 了，所以我可能遗漏了一些明显的、愚蠢的东西。
This is a Qt Mobile app that I'm writing in Qt Creator 2.4.0, Based on Qt 4.7.4 (64 bit) Built on Dec 20 2011 at 11:14:33.
这是我正在编写的 Qt Mobile 应用程序Qt Creator 2.4.0, Based on Qt 4.7.4 (64 bit) Built on Dec 20 2011 at 11:14:33。
#include <QFile>
#include <QString>
#include <QTextStream>
#include <QIODevice>
#include <QStringList>
QFile file("words.txt");
QStringList words;
if( file.open( QIODevice::ReadOnly ) )
{
QTextStream t( &file );
while( !t.eof() ) {
words << t.readline();
}
file.close();
}
What am I missing? Thanks in advance.
我错过了什么？提前致谢。
回答by Mat
You can't have free-standing code like that. All code needs to go into functions.
你不能有这样的独立代码。所有代码都需要进入函数。
Wrap all that in a mainfunction and you should be ok once you've fixed your use of QTextStream(it has no eofmethod, and it doesn't have a readlinemethod either - please look at the API docsthat come with usage examples).
将所有这些都包装在一个main函数中，一旦你确定了你的使用，你应该QTextStream没问题（它没有eof方法，也没有readline方法 - 请查看使用示例附带的API 文档）。
#include <QFile>
#include <QString>
#include <QTextStream>
#include <QIODevice>
#include <QStringList>
int main()
{
QFile file("words.txt");
QStringList words;
if( file.open( QIODevice::ReadOnly ) )
{
QTextStream t( &file );
QString line = t.readLine();
while (!line.isNull()) {
words << line;
line = t.readLine();
}
file.close();
}
}
