c++ - Deallocating memory -

for project have implement bitset class. code far is:

header file

#ifndef bitset_h_ #define bitset_h_ #include <string> #include <cmath>  using namespace std;  // container class hold , manipulate bitsets class bitset { public:     bitset();     bitset(const string);     ~bitset();      // returns size of bitset     int size();      // sets bitset equal specified value     void operator= (const string);      // accesses specific bit bitset     bool operator[] (const int) const;  private:     unsigned char *bitset;     int set_size;     // sets bitset equal specified value     void assign(const string); }; #endif /* bitset_h_ */ 

source file

#include "bitset.h"  bitset::bitset() {     bitset = null; }  bitset::bitset(const string value) {     bitset = null;     assign(value); }  bitset::~bitset() {     if (bitset != null) {         delete[] bitset;     } }  int bitset::size() {     return set_size; }  void bitset::operator= (const string value) {     assign(value); }  bool bitset::operator[] (const int index) const {     int offset;      if (index >= set_size) {         return false;     }      offset = (int) index/sizeof(unsigned char);     return (bitset[offset] >> (index - offset*sizeof(unsigned char))) & 1; }  void bitset::assign(const string value) {     int i, offset;      if (bitset != null) {         delete[] bitset;     }      bitset = new unsigned char[(int) ceil(value.length()/sizeof(unsigned char))];      (i = 0; < value.length(); i++) {         offset = (int) i/sizeof(unsigned char);         if (value[i] == '1') {             bitset[offset] |= (1 << (i - offset*sizeof(unsigned char)));         } else {             bitset[offset] &= ~(1 << (i - offset*sizeof(unsigned char)));         }     }      set_size = value.length(); } 

my problem delete statements in both deconstructor , assign method core dump. not necessary deallocate memory? i've read far it's necessary use delete command whenever call new.

edit: i've changed code above reflect 1 of fixes. added bitset = null in constructor. fixed core dump in assign method i'm still getting errors in deconstructor.

i think should initialize bitset null in second constructor.

why?

because pointer variable won't initialized null. may trying delete[] random memory address when use second constructor.

so should have:

bitset::bitset(const string value) : bitset(null) {     assign(value); }