对指针调用delete之后要记得把指针赋值为nullptr
否则，如果这个指针被重复delete，会死机。
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#include <iostream>
using
std::cout;
using
std::endl;
using
std::ostream;
class
Tree {
int
height;
public
:
Tree(
int
treeHeight) : height(treeHeight) {
cout << __func__ <<
"(), this = "
<<
this
<< endl;
}
~Tree() { cout <<
"~Tree()\n"
; }
#if 0
friend
ostream&
operator<<(ostream& os,
const
Tree* t) {
return
os <<
"Tree height is: "
<< t->height << endl;
}
#else
friend
ostream&
operator<<(ostream& os,
const
Tree& t) {
return
os <<
"Tree height is: "
<< t.height << endl;
}
#endif
};
int
main() {
Tree* t =
new
Tree(40);
delete
t;
//t = nullptr;
delete
t;
}
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运行结果：
frank@userver:~/project/test/cpp/new_del$ ./a.out
Tree(), this = 0x13b2010
~Tree()
~Tree()
*** Error in `./a.out': double free or corruption (fasttop): 0x00000000013b2010 ***
Aborted (core dumped)
本文转自FrankNie0101 51CTO博客，原文链接：http://blog.51cto.com/frankniefaquan/1936943，如需转载请自行联系原作者
