C++ delete [] 与 delete

简介

对于普通数据类型数组 使用 delete [] pa 和 delete pa, 都不会产生内存泄露. 对于自己定义的对象数组, 会产生内存泄露.

环境

g++ , valgrind 来查看是否产生了内存泄露

参考链接

https://www.cnblogs.com/sura/archive/2012/07/03/2575448.html

code

#include <iostream>
#include <ctime>
#include <algorithm>
#include <stdlib.h>
#include <vector>
#include <string>
#include <sstream>
#include <map>
#include <unordered_set>
#include <set>
#include <unordered_map>
#include <limits>
#include <stack>
#include <list>
#include <queue>

using LL = long long;
using ULL = unsigned long long;
//using PII = pair<int,int>;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const int dir[4][2] = {{1,0},{-1,0},{0,1},{0,-1}};
using namespace std;
// 大于等于k的最小整数

class Test{
public:
    int a;
    Test() {
        a = 0;
    }
    ~Test(){
        cout << "~Test()" << endl;
    }
};

int main() {
    int *p = new int[5];
    cout << sizeof(p) << endl;
    delete p;

    int *pa = new int[5];
    cout << sizeof(pa) << endl;
    delete [] pa;

    Test *pb = new Test[5];
    cout << sizeof(pb) << endl;
    delete [] pb;

    Test *pc = new Test[5];
    cout << sizeof(pc) << endl;
    delete pc; // 会导致内存泄露 且出现段错误 segmentation fault (core dumped)
    /*
    ==207912== LEAK SUMMARY:
    ==207912==    definitely lost: 28 bytes in 1 blocks
    ==207912==    indirectly lost: 0 bytes in 0 blocks
    ==207912==      possibly lost: 0 bytes in 0 blocks
    ==207912==    still reachable: 0 bytes in 0 blocks
    ==207912==         suppressed: 0 bytes in 0 blocks
    */
    return 0;
}

TIP

这里显示的sizeof都是8显示的都是指针的大小. 因为是64位系统, 使int达到了8个字节的长度.