删除数组指针时，我的程序没有 return 0

Question

当我尝试删除声明为

的数组指针时

short *width = NULL;
width = new short[lenght];
delete[] width;

程序停止在删除部分和returns一个随机数。

这是我的全部程序

int main(){
    short **junction = NULL, *width = NULL, length = 0;
    ifstream input;

    input.open("sample_input.txt");
    if(!input)
        cout << "No such a file named \"sample_input.txt\"" << endl;
    else if(input >> length){
        junction = new short*[length];
        width = new short[length];
        string str; 
        for(int i = 0; i - 1 < length && getline(input, str); i++){
            istringstream ss(str);
            width[i - 1] = (str.size() + 1) / 2; //numbers can be two char, so in this case, here we allocate more than necessary memory
            junction[i - 1] = new short[width[i - 1]];
            for(int j = 0; j < width[i - 1]; j++){
                if(ss.eof()){
                    junction[i - 1][j] = -1; // -1 is the key value of emtpy spaces
                    continue;
                }
                ss >> junction[i - 1][j];
            }
        }
    }
    input.close();

    /*
    for(int i = 0; i < length; i++)
        delete[] junction[i];
    delete[] junction;
    delete[] width;
    */

    return 0;
}

评论部分有问题，我分别尝试了那些删除语句只是部分正在运行但不像我预期的那样这是我的示例输入：

Answer 1

你的代码实际上应该没问题。请向我们展示整个程序。

florian@florian-desktop:~$ cat -n test2.cpp
     1  #include <iostream>
     2  int main()
     3  {
     4  const int length = 4;
     5  short *width = NULL;
     6  width = new short[length];
     7  delete[] width;
     8  }
florian@florian-desktop:~$ valgrind ./a.out 
==22630== Memcheck, a memory error detector
==22630== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==22630== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==22630== Command: ./a.out
==22630== 
==22630== 
==22630== HEAP SUMMARY:
==22630==     in use at exit: 0 bytes in 0 blocks
==22630==   total heap usage: 2 allocs, 2 frees, 72,712 bytes allocated
==22630== 
==22630== All heap blocks were freed -- no leaks are possible
==22630== 
==22630== For lists of detected and suppressed errors, rerun with: -s
==22630== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

Valgrind 显示所有保留的内存都已正确释放。

-- 更新：

我更正了您的完整代码：

#include <iostream>
#include <sstream>
#include <fstream>
using namespace std;
int main() {
short **junction = NULL, *width = NULL, length = 12;
    ifstream input;

    input.open("sample_input.txt");
    if(!input)
        cout << "No such a file named \"sample_input.txt\"" << endl;
    else if(input >> length){
        junction = new short*[length];
        width = new short[length];
        string str; 
        for(int i = 0; i < length && getline(input, str); i++){
            istringstream ss(str);
            width[i] = (str.size() + 1) / 2; //numbers can be two char, so in this case, here we allocate more than necessary memory
            junction[i] = new short[width[i]];
            for(int j = 0; j < width[i]; j++){
                if(ss.eof()){
                    junction[i][j] = -1; // -1 is the key value of emtpy spaces
                    continue;
                }
                ss >> junction[i][j];
            }
        }
    }
    input.close();

    
    for(int i = 0; i < length; i++)
        delete[] junction[i];
    delete[] junction;
    delete[] width;
    

    return 0;
}

删除数组指针时，我的程序没有 return 0

My programs doesn't return 0 when deleting array pointer

c++

pointers

runtime-error

-- 更新：