delete giving core dump

[gabhaad]

Hi folks,
Can someone help with below code giving core dump on delete statement in destructor.
CODE:

#include <iostream>
using namespace std;
class my_str{
  int l1, l2;
  char * arr1;
  int * arr2;
  public:
  my_str(){//default ctr
      l1 = 0; l2 = 0;
      arr1 = new char[10];
      arr2 = new int[3];
  }
  my_str(const my_str & tmp){//copy ctr
      l1 = tmp.l1;
      l2 = tmp.l2;
      arr1 = new char[l1];
      arr2 = new int[l2];
      for(int i=0; i<l1; i++){
          arr1[i] = tmp.arr1[i];
      }
      for(int i=0; i<l2; i++){
          arr2[i] = tmp.arr2[i];
      }
  }
  int count_vowels(char * tmp){
      int count=0;
      for(int i = 0; tmp[i]!='\0'; i++){
          if(tmp[i]=='a'||tmp[i]=='e'||tmp[i]=='i'||tmp[i]=='o'||tmp[i]=='u')
          {
              count++;
          }
      }
      return count;
  }
  void push_str(char * inp){
      int count = count_vowels(inp);
      for(int i=0; i<l2; i++){
          if(arr2[i] == count){
              cout<<"\nCannot insert. Need Unique Vowels";
              return;
          }
      }
      int tmp_len = l1;
      int i;
      for(i=0; inp[i] != '\0'; i++)
      {
          arr1[tmp_len] = inp[i];
          tmp_len++;
      }
      l1 = l1+i;
      arr2[l2] = count;
      l2++;
      return;
  }
  void print_str()
  {
      cout<<"l1 : "<<l1<<"\nString is : ";
      for(int i=0; i<l1; i++){
          cout<<arr1[i];
      }
      cout<<endl;
      cout<<"l2 : "<<l2<<"\nVowel Count array : ";
      for(int i=0; i<l2; i++){
          cout<<arr2[i]<<" ";
      }
  }
  ~my_str(){//dtr
      cout<<"\nInside dtr"<<endl;
      fflush(stdout);
      delete []arr2;//this line is causing core dump
      delete []arr1;
      arr1=NULL;
      arr2=NULL;
      cout<<"exiting dtr";
      fflush(stdout);
  }
};
//In a custom string object, only strings with unique num of vowels must be allowed to be inserted.
int main()
{
    my_str S1;
    S1.push_str("trees");
    S1.push_str("animals");
    S1.push_str("mesopotemia");
    cout<<"\nPrinting S1"<<endl;
    S1.print_str();
    
    my_str S2 = S1;
    S2.push_str("egypt");
    S2.push_str("jaguar");
    cout<<"\nPrinting S2 : "<<endl;
    S2.print_str();
    
    return 0;
}

OUTPUT :
Printing S1
l1 : 23
String is : treesanimalsmesopotemia
l2 : 3
Vowel Count array : 2 3 6
Cannot insert. Need Unique Vowels
Printing S2 :
l1 : 28
String is : treesanimalsmesopotemiaegypt
l2 : 4
Vowel Count array : 2 3 6 1
Inside dtr
*** Error in `./a.out': munmap_chunk(): invalid pointer: 0x0000000000715c80 ***
Aborted (core dumped)

[keskiverto]

Unformatted text is hard to read. Please add code tags. See http://www.cplusplus.com/articles/jEywvCM9/

[jonnin]

I don't see where l2 is set to a useful value.
arr2 = new int[l2];

[ne555]

$ valgrind ./a.out
==5368== Memcheck, a memory error detector
==5368== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==5368== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright info
==5368== Command: ./a.out
==5368== 
==5368== Invalid write of size 1
==5368==    at 0x10951C: my_str::push_str(char*) (foo.cpp:48)
==5368==    by 0x1092A3: main (foo.cpp:84)
==5368==  Address 0x4d4dc8a is 0 bytes after a block of size 10 alloc'd
==5368==    at 0x483950F: operator new[](unsigned long) (vg_replace_malloc.c:423)
==5368==    by 0x10942D: my_str::my_str() (foo.cpp:12)
==5368==    by 0x10927E: main (foo.cpp:82)
...

	void push_str(char *inp) {
		int count = count_vowels(inp);
		for(int i = 0; i < l2; i++) {
			if(arr2[i] == count) {
				cout << "\nCannot insert. Need Unique Vowels";
				return;
			}
		}
		int tmp_len = l1;
		int i;
		for(i = 0; inp[i] != '\0'; i++) {
			arr1[tmp_len] = inp[i]; //line 48
			tmp_len++;
		}
		l1 = l1 + i;
		arr2[l2] = count;
		l2++;
		return;
	}

¿how big is `arr1'? ¿how many elements are you trying to insert? ¿have you ever heard of std::vector?
same issue with `arr2'

also, arr{1,2} are terrible names.

[jonnin]

arr{1,2} are terrible names.

well, if he had worked a yohoho in there too, maybe...