Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: c++ assignment operator overloading
Top Forums Programming c++ assignment operator overloading Post 302481656 by Corona688 on Saturday 18th of December 2010 09:19:13 PM
Old 12-18-2010
Since the class doesn't know how much memory is allocated to mem, you can't. You have to store the size somewhere.

I'd do it like this:

Code:
#include <stdio.h>
#include <string.h>

class A {
public:
   int * mem;
   int size;
   A(int isize=0) : mem(NULL), size(0) {
      if(isize > 0)
      {
        mem=new int[isize];
        size=isize;
      }
   }

   A &operator=(const A &o)
   {
      if(size > 0) // Free existing memory
      {
         delete mem;
         size=0;
      }

      if(o.size > 0) // Copy other memory if it exists
      {
         mem = new int[o.size];
         size=o.size;
         memcpy(mem, o.mem, o.size * sizeof(int));
      }

      return(*this);
   }

  ~A() {
     if (mem!=NULL)
     {
       printf("Freeing %p\n", mem);
       delete mem;
     }
   }
};

int main(void)
{
    A a(100), b;

    b=a;
}

Last edited by Corona688; 12-18-2010 at 10:39 PM.. Reason: forgot the return statement
 

10 More Discussions You Might Find Interesting

1. Programming

what is diff b/w copy constructor and overloaded assignment operator

Helo i m new in c++. i m confuse about what is exact difference b/w copy constructor and overloaded assignment operator. Regards, Amit (3 Replies)
Discussion started by: amitpansuria
3 Replies

2. Shell Programming and Scripting

scalar variable assignment in perl + { operator

When reading over some perl code in a software document, I came across an assignment statement like this $PATH = ${PROJECT}/......./.... In this particular form of scalar variable assignment, what does the curly braces operators do ? Also, what is the benefit in doing scalar assignment this... (3 Replies)
Discussion started by: JamesGoh
3 Replies

3. AIX

xlC compilation error when dealing with operator overloading

Hi, I have a piece of C++ code that can be compiled using g++, but reports an error when compiled with xlC: xlC -DHAVE_CONFIG_H -I../SRC -I../include -DNoChange -DSPRNG_MPI -q64 -DLONG64=long -I/usr/lpp/ppe.poe/include -DLONG64=long -c -o libsprng_a-bignum.o bignum.cpp "bignum.cpp",... (1 Reply)
Discussion started by: luop0812
1 Replies

4. Programming

C++ Optr Overloading

Hi All, In C++ one operator can be overloaded, but it can't be overloaded by it's own derieved class Please let me know operator. Thanks, Naga:cool: (1 Reply)
Discussion started by: Nagapandi
1 Replies

5. Programming

Delete operator overloading with multiple arguments.

Hi, I have an requirement to overload the delete operator in C++, but it should also accept the sizeof() the object that is to be deleted. Actually I am trying to built a custom memory allocator and deallocator like a pool, which makes me to overload the delete operator. Small example of the... (1 Reply)
Discussion started by: kapilkumawat
1 Replies

6. UNIX for Dummies Questions & Answers

mysqld overloading cpu of VPS

Hi bros I have a VPS 512mb (Burst 2GB) with Kloxo installed and hosting few sites on it with not much traffic I am facing high cpu load for the last few days and seems mysqld is overloading the cpu Any suggestion will be appreciated Regards Rizwan Top output is as under top -... (2 Replies)
Discussion started by: rizwan65
2 Replies

7. Programming

Need to understand the overloaded assignment operator behavior

Hi, In the following code, class A { public: void operator=(const A& rhs) { if (this == &rhs) cout << "self-assigned"; } }; class B { A a; // should not be a pointer member, (i.e) A* a }; int main() { B b; b = b; // Ans: self-assigned } I am really... (5 Replies)
Discussion started by: royalibrahim
5 Replies

8. Shell Programming and Scripting

Assignment operator without operand

Does anyone know how this line in bash works? local gotbase= force= nicelevel corelimit local pid base= user= nice= bg= pid_file= local cgroup= These lines are part of the daemon function inside the "functions" file at /etc/init.d in RH. (3 Replies)
Discussion started by: Rameshck
3 Replies

9. Shell Programming and Scripting

Bash variable assignment failure/unary operator expected

I have a little code block (executing on AIX 7.1) that I cannot understand why the NOTFREE=0 does not appear to be assigned even though it goes through that block. This causes a unary operator issue. #!/bin/bash PLATFORM="AIX" NEEDSPC=3000 set -x if ; then lsvg | grep -v rootvg | while... (6 Replies)
Discussion started by: port43
6 Replies

10. Programming

C++ operator overloading error

hi, I defined my own String class and overloaded the output operator with friend ostream& operator<<(ostream& os, const myString& str); //overloads the << operator so it can be used to output values of type myString which works fine. Until I try to execute the following statement: // +... (6 Replies)
Discussion started by: milhan
6 Replies

LEARN ABOUT OSX

ppmtosixel

ppmtosixel(1)						      General Commands Manual						     ppmtosixel(1)

NAME

       ppmtosixel - convert a portable pixmap into DEC sixel format

SYNOPSIS

       ppmtosixel [-raw] [-margin] [ppmfile]

DESCRIPTION

       Reads  a  portable  pixmap  as input.  Produces sixel commands (SIX) as output.	The output is formatted for color printing, e.g. for a DEC
       LJ250 color inkjet printer.

       If RGB values from the PPM file do not have maxval=100, the RGB values are rescaled.  A printer control header and a color assignment table
       begin the SIX file.  Image data is written in a compressed format by default.  A printer control footer ends the image file.

OPTIONS

       -raw   If  specified,  each  pixel  will  be explicitly described in the image file.  If -raw is not specified, output will default to com-
	      pressed format in which identical adjacent pixels are replaced by "repeat pixel" commands.  A raw file is often an order	of  magni-
	      tude larger than a compressed file and prints much slower.

       -margin
	      If  -margin  is not specified, the image will be start at the left margin (of the window, paper, or whatever).  If -margin is speci-
	      fied, a 1.5 inch left margin will offset the image.

PRINTING

       Generally, sixel files must reach the printer unfiltered.  Use the lpr -x option or cat filename > /dev/tty0?.

BUGS

       Upon rescaling, truncation of the least significant bits of RGB values may result in poor color conversion.  If the original PPM maxval was
       greater	than  100,  rescaling  also reduces the image depth.  While the actual RGB values from the ppm file are more or less retained, the
       color palette of the LJ250 may not match the colors on your screen.  This seems to be a printer limitation.

SEE ALSO

       ppm(5)

AUTHOR

       Copyright (C) 1991 by Rick Vinci.

								   26 April 1991						     ppmtosixel(1)
All times are GMT -4. The time now is 07:12 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy