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#2
TheEleven2007-11-05 15:10
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vector<Student_info> students, fails;
......
fails = extract_fails(students);
......
fails = extract_fails(students);
用Dev-Cpp（Gcc3.4.5）编译时，就会提示如下警告（注，是加-Wall参数才会出现的警告，不加则没有）：
C:\Dev-Cpp\include\c++\3.4.5\bits\stl_vector.h In member function `std::vector<_Tp, _Alloc>& std::vector<_Tp, _Alloc>::operator=(const std::vector<_Tp, _Alloc>&) [with _Tp = Student_info, _Alloc = std::allocator<Student_info>]':
715 C:\Dev-Cpp\include\c++\3.4.5\bits\stl_vector.h [Warning] '__result' might be used uninitialized in this function
82 C:\Dev-Cpp\include\c++\3.4.5\bits\stl_uninitialized.h [Warning] '__cur' might be used uninitialized in this function
82 C:\Dev-Cpp\include\c++\3.4.5\bits\stl_uninitialized.h [Warning] '__cur' might be used uninitialized in this function
715 C:\Dev-Cpp\include\c++\3.4.5\bits\stl_vector.h [Warning] '__result' might be used uninitialized in this function
82 C:\Dev-Cpp\include\c++\3.4.5\bits\stl_uninitialized.h [Warning] '__cur' might be used uninitialized in this function
82 C:\Dev-Cpp\include\c++\3.4.5\bits\stl_uninitialized.h [Warning] '__cur' might be used uninitialized in this function
一旦我将代码改写成如下的形式：
vector<Student_info> students;
......
vector<Student_info> fails(extract_fails(students));
......
vector<Student_info> fails(extract_fails(students));
就不会警告了，这个是什么原因造成的呢？