CODEWITHSUNDEEP
c++
user13675
user13675

Reputation: 143

Destructor for char arrays Error

I have the following code:

class Class 
{
private:
    char* str;
public:
    Class(const char* src) 
    {
        str = new char[strlen(src)];
        strcpy(str,source);
    }
    ~Class() {
        delete [] str;
    }
};

A main function calls the constructor with some string. Upon exiting, the runtime crashes on the destructor.The error message is:

pointer being freed was not allocated

How can I solve this

Upvotes: 0

Views: 3591

Answers (3)

Pabitra Dash
Pabitra Dash

Reputation: 1513

The copy constructor should like this.

Class(const char* src) 
{
    str = new char[strlen(src) + 1];// +1 is missed in original code.
    strcpy(str,source); // copy and append '\0'
}

Upvotes: 0

Constantine Kuznetsov
Constantine Kuznetsov

Reputation: 187

you must check a pointer to NULL , if os cant allocate smemory to array of char str . str being NULL, delete[] null pointer - problem.

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
class Class 
{
    private:
    char* str;
    public:
    Class(const char* src) 
    {
        str = new char[strlen(src)];
        if(str) {
            strcpy(str,src);
        }
    }
    char* getstr() { return str; }
    ~Class() {
        if(str) {
            delete [] str;
        }    
    }
};
int main() {
    Class te("sdfs\n");
    printf("%s",te.getstr());
    return 0;
}

Upvotes: -1

Dimitrios Bouzas
Dimitrios Bouzas

Reputation: 42899

Just look how nicer and safer your code becomes with use of std::string:

class Class {
    std::string str;
public:
    Class(char const *src) : str(src) {}
};

And you don't need to worry about deleting memory, about allocating +1 character space for the \0 character at the end etc.

Upvotes: 4

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