segment fault with the program

[sanddune008]

I am receiving segment fault with this program

#include <iostream>
#include <new>
#include <cstdlib>

using namespace std;

class ar
{
	int *p;
	int size;
	public:
	ar(int sz){
		cout<<"Initializing array in Constructor\n";
		try {
			p = new int[sz];
		}
		catch(bad_alloc xa){
		cout <<"Allocation Failure\n";
		exit(EXIT_FAILURE);	
		}
	}
	ar (const ar &a);
        ~ar(){cout << "Destructor is called\n";delete []p;}
	void set_val(int i,int j){if(i>0&&i<size) p[i]=j; }
        void get_val(int i){cout<<"Val is :"<<p[i];cout<<"\t";}
};


ar::ar(const ar &a)
{
	int i;
	try 
	{
		p = new int[a.size];
	}
	catch(bad_alloc sp)
	{
		cout<<"Allocation Failure\n";
		exit(EXIT_FAILURE);
	}
	for (i=0;i<a.size;i++) p[i]=a.p[i];
}

int main()
{
	ar a(5),b(5);
        
        b=a;	

        for(int i=0;i<5;i++)
        	a.set_val(i,i);        
        
	b.set_val(2,3);          
	b.set_val(3,63);          
	b.set_val(4,983);          

        for(int i=0;i<5;i++)
        	a.get_val(i);        
        cout<<"\n============ Copy Constructor goes here==============\n"  ;
        ar c(b);        
         
	for(int i=0;i<5;i++)
        	c.set_val(i,i);        
        
	//c.set_val(2,3);          
	//c.set_val(3,63);          
	//c.set_val(4,983);          

        for(int i=0;i<5;i++)
        	a.get_val(i);
	return 0;
}

1. I am getting segment fault after the following statement
cout<<"\n============ Copy Constructor goes here==============\n" ;

Thanks in advance

[jimblumberg]

Where do you assign a value to the member variable size? Shouldn't it be set in the constructor?


Jim

[sanddune008]

thanks...........

but the segmentation fault still persists even after adding.

[dmh2000]

thanks...........

but the segmentation fault still persists even after adding.

1. you need to set 'size' in both constructors

2. since you don't have an assignment operator defined, you get a compiler defined assignment, so when you assign b = a the original pointer that b had is overwritten with the pointer from a. then at the end of your program when the desttructors are called, that pointer is released twice which can cause a fault. plus your original pointer from 'b' is lost and never deallocated.

you need to define an assignment operator that handles the transfer of pointers properly.

[Elysia]

SourceForge.net: Raw pointer issues - cpwiki