STL中的map调用erase(it)，当value值为指针时，释放内存：
1 #include <iostream>
2 #include <map>
3 #include <string>
4
5 using namespace std;
6 struct value{
7 int i;
8 std::string test;
9 };
10
11 int main()
12 {
13 std::map<int, value*> test_map;
14 for(int i=0; i<10; ++i){
15 value* tmp = new value();
16 tmp->i = i;
17 tmp->test = "test";
18 test_map.insert(make_pair(i, tmp));
19 }
20
21 for(std::map<int, value*>::iterator it=test_map.begin(); it!=test_map.end();){
22 std::cout << "first " << it->first << " second " << (it->second)->i <<" "<< (it->second)->test << std::endl;
23 delete it->second;
24 it->second = NULL;
25 //test_map.erase(it); //迭代器失效；
26 test_map.erase(it++); //防止迭代器失效，切记、切记
27 }
28
29 return 0;
30 }
31
32 [email protected]:~/cp/test# g++ map3.cpp -g -Wall
33 [email protected]:~/cp/test# ls -lt a.out
34 -rwxr-xr-x 1 root root 87224 Jul 9 11:00 a.out
35 [email protected]:~/cp/test# valgrind --tool=memcheck --leak-check=full ./a.out
36 ==28426== Memcheck, a memory error detector
37 ==28426== Copyright (C) 2002-2011, and GNU GPL‘d, by Julian Seward et al.
38 ==28426== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info
39 ==28426== Command: ./a.out
40 ==28426==
41 first 0 second 0 test
42 first 1 second 1 test
43 first 2 second 2 test
44 first 3 second 3 test
45 first 4 second 4 test
46 first 5 second 5 test
47 first 6 second 6 test
48 first 7 second 7 test
49 first 8 second 8 test
50 first 9 second 9 test
51 ==28426==
52 ==28426== HEAP SUMMARY:
53 ==28426== in use at exit: 0 bytes in 0 blocks
54 ==28426== total heap usage: 30 allocs, 30 frees, 930 bytes allocated
55 ==28426==
56 ==28426== All heap blocks were freed -- no leaks are possible
57 ==28426==
58 ==28426== For counts of detected and suppressed errors, rerun with: -v
59 ==28426== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)
时间： 2024-10-24 18:51:38