Destructor gets called before the end of scope

Question

for some reason, after creating an object in main func., the destructor gets called right away, isn't it supposed to get called only when main finishes? thanks

code:

#include <iostream>
#include <cstring>
#include <vector>
using namespace std; 


class check{                                                   //create class check
public:
    string m_bank_name;
    int m_check_number;
    int m_branch_number;
    char* m_check_sum;



    check ( string bank_name, int check_number, int branch_number, char* check_sum){
        int a_size = (strlen(check_sum)+1);
        m_check_sum = new char[a_size]();
        for (int i=0;i<a_size;i++)
        {
            m_check_sum[i]=check_sum[i];
        }
        m_bank_name= bank_name;
        m_check_number = check_number;
        m_branch_number = branch_number;
    }

    ~check (){
        delete [] m_check_sum;
        cout<<"deleted!"<<endl;     
        }
};

void main(){

    check ob1= check("poalim",809877,12,"4578");
    cout<<ob1.m_check_sum<<endl;
    getchar();
}

If you change the type of `m_check_sum` to `std::string` (or `std::vector` or some other type with value semantics), then you won't need a destructor, you won't need to follow the [Rule of Three](http://en.wikipedia.org/wiki/Rule_of_three_(C%2B%2B_programming)), and you won't care about the destructor being called too early or too often. — Robᵩ, Apr 24 '13 at 17:14

score 5 · Accepted Answer · edited May 23 '17 at 11:53

5

This expression

check("poalim",809877,12,"4578")

creates a temporary object that gets destroyed right after the full expression (;)

Before being destroyed, it is copied to ob1, which is destroyed at the end of the main function.

Perhaps you meant to write

int main(){ //note the correct return type of main
  check ob1("poalim",809877,12,"4578"); //direct constructor call
  cout<<ob1.m_check_sum<<endl;
  getchar(); 
}

I really suggest that you should read a good book on C++ fundamentals.

edited May 23 '17 at 11:53

Community

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answered Apr 24 '13 at 17:07

Armen Tsirunyan

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how come it creates a temporary object? how should I initialize a "check" object in a way that won't create a temp object? – user1887990 Apr 24 '13 at 17:09
oh, yea are right, guess i'm too tired, thanks, i'll accept the answer in 8 mins when it'll let me! – user1887990 Apr 24 '13 at 17:12

Destructor gets called before the end of scope

1 Answers1