初始化列表导致的内存泄漏？

Question

根据valgrind的说法，我的代码中存在内存泄漏，它们全部来自类的构造函数；这是它的代码：

  School::School(unsigned int NumberOfClasses[]) :
        first(*new Grade<Student, std::equal_to<Student>>(NumberOfClasses[0])),
        second(*new Grade<Student, std::equal_to<Student>>(NumberOfClasses[1])),
        third(*new Grade<Student, std::equal_to<Student>>(NumberOfClasses[2])) {

}

Grade是我创建的特殊数组模板，它同时获取一个元素（在本例中为Student）和该元素的比较函数（我也提供了）；它既有构造函数，也有析构函数，可以在没有内存泄漏的情况下工作。这是构造函数的标题：

Grade<Element, Compare> :: Grade(unsigned int size);

因为我的学校是3年级，所以其析构函数是= default;

这是我从valgrind得到的：

    8 bytes in 1 blocks are indirectly lost in loss record 1 of 6
==21426==    at 0x4C2A888: operator new[](unsigned long) (vg_replace_malloc.c:423)
==21426==    by 0x4041B8: Grade<BmbSchool::Student, std::equal_to<BmbSchool::Student> >::Grade(unsigned int) (GradeImp.h:9)
==21426==    by 0x40298B: BmbSchool::School::Grade(unsigned int*) (School.cpp:27)
==21426==    by 0x405B6C: main (BmbSchool.cpp:148)

类似的，我得到的另一种错误是：

==21426== 32 (24 direct, 8 indirect) bytes in 1 blocks are definitely lost in loss record 3 of 6
==21426==    at 0x4C2A1E3: operator new(unsigned long) (vg_replace_malloc.c:334)
==21426==    by 0x402974: BmbSchool::School::Grade(unsigned int*) (School.cpp:28)
==21426==    by 0x405B6C: main (BmbSchool.cpp:148)

有任何意义吗？我该如何解决？我可以假设定义数组时不会抛出bad_alloc异常。

编辑：学校的定义是-

    Grade<Student, std::equal_to<Student>> first;
    Grade<Student, std::equal_to<Student>> second;
    Grade<Student, std::equal_to<Student>> third;

谢谢！

Answer 1

泄漏是由于您滥用new。您正在动态分配3个Grade对象，但是随后取消引用指针来复制构造3个数据成员。您永远不会delete您已new编辑过的对象。

在这种情况下，您根本不需要new，因此请摆脱它。只需将所需的值直接传递给数据成员构造函数：

School::School(unsigned int NumberOfClasses[]) :
    first(NumberOfClasses[0]),
    second(NumberOfClasses[1]),
    third(NumberOfClasses[2])
{
}