[c-prog] query on prefix and post fix operator overloading
Hi,
I have a small query. why we need to return reference in prefix operator
overloading. Because, when we call as ++obj , the operator ++ method will be
called and we increment the values using this pointer. I will paste the code.
Please let me know where I failed.
#includestdio.h
#includeconio.h
#includeiostream
using namespace std;
class mydata
{
private:
int x,y;
public:
mydata()
{
coutI m i9n consendl;
}
mydata(int a,int b):x(a),y(b)
{
coutI m in parmendl;
}
void sow()
{
coutx = x y = yendl;
}
mydata operator +(mydata obj)
{
x=x+obj.x;
y=y+obj.y;
return *this;
}
void operator ++()
{
this-x++;
this-y++;
}
friend mydata operator +(int val,mydata obj)
{
obj.x=val+obj.x;
obj.y=val+obj.y;
return obj;
}
mydata(mydata obj)
{
this-x=obj.x;
this-y=obj.y;
}
mydata operator =(mydata obj)
{
if(this!=obj)
{
this-x=obj.x;
this-y=obj.y;
}
return *this;
}
};
void main()
{
mydata obj1(2,4);
obj1.sow();
mydata obj2(4,7);
obj2.sow();
obj1=obj1+obj2;
obj1.sow();
#ifdef _DEBUG
__asm{int 3}
#endif
++obj1;
obj1.sow();
mydata obj3=2+obj1;
obj3.sow();
}
GopiKrishna Komanduri
Software engineer
[EMAIL PROTECTED]
--- On Thu, 27/11/08, Gopi Krishna Komanduri [EMAIL PROTECTED] wrote:
From: Gopi Krishna Komanduri [EMAIL PROTECTED]
Subject: [c-prog] query on Exception handling (in constructor and desctructor)
To: c-prog@yahoogroups.com
Date: Thursday, 27 November, 2008, 10:24 AM
Hi,
I have a query related to exceptional handling. I pasted the code I tried
following this mail.
My intention is , what happens in a sistuation when any exception is caught in
main , so while destructing the objects till that instant again if any
exception is caught (stack unwinding concept).
similary in constructor. For constructor I know that the desctructors of the
sub objects will be called . But how that exception is handled .
#includestdio. h
#includeconio. h
#includeiostream
using namespace std;
class var1
{
public:
var1()
{
coutI m in var1 concendl;
}
~var1()
{
coutI m in var1 descendl;
}
};
class MyCls
{
public:
var1 *obj;
MyCls():obj( NULL)
{
obj=new var1();
coutI m in consendl;
}
~MyCls()
{
coutI m in descendl;
throw excepto;
delete obj;
coutDeleted objendl;
}
};
void main()
{
try
{
MyCls obj;
coutObj Createdendl;
throw error;
coutObj after throwing errendl;
}
catch(char *x)
{
coutxendl;
}
catch(...)
{
coutI m in lastendl;
}
}
GopiKrishna Komanduri
Software engineer
Hyderabadgopikomand [EMAIL PROTECTED] com
--- On Tue, 25/11/08, Brett McCoy [EMAIL PROTECTED] com wrote:
From: Brett McCoy [EMAIL PROTECTED] com
Subject: Re: [c-prog] Exception handling
To: [EMAIL PROTECTED] com
Date: Tuesday, 25 November, 2008, 9:29 PM
On Tue, Nov 25, 2008 at 9:10 AM, crystalcat_75
crystalcat_ 75@ yahoo.co. in wrote:
Following program is showing an error while running in turbo c :
undefined symbol for try
statement missing after try .
I don't think Turbo C supports exceptions. You need to upgrade to a
modern compiler like Dev-C++ or MS Visual C++ Express (they are free)
and not use something that is 15+ years old.
-- Brett
- - - - - -
In the rhythm of music a secret is hidden;
If I were to divulge it, it would overturn the world.
-- Jelaleddin Rumi
Add more friends to your messenger and enjoy! Go to http://messenger.
yahoo.com/ invite/
[Non-text portions of this message have been removed]
Add more friends to your messenger and enjoy! Go to
http://messenger.yahoo.com/invite/
[Non-text portions of this message have been removed]
[c-prog] Re: query on Exception handling (in constructor and desctructor)
Gopi Krishna Komanduri [EMAIL PROTECTED] wrote: Hi, I have a query related to exceptional handling. I pasted the code I tried following this mail. My intention is , what happens in a sistuation when any exception is caught in main , so while destructing the objects till that instant again if any exception is caught (stack unwinding concept). http://www.parashift.com/c++-faq-lite/exceptions.html#faq-17.3 -- Peter
[c-prog] Re: query on prefix and post fix operator overloading
Gopi Krishna Komanduri [EMAIL PROTECTED] wrote: I have a small query. why we need to return reference in prefix operator overloading. http://www.parashift.com/c++-faq-lite/operator-overloading.html#faq- 13.14 http://www.parashift.com/c++-faq-lite/newbie.html#faq-29.3 -- Peter
Re: Res: [c-prog] Re: integer promotions
--- peternilsson42 wrote: -Wconversion Warn for implicit conversions that may alter a value. ... Integral promotions don't alter the value. Maybe you need -Wsign-conversion gcc -Wall -Wsign-conversion problem.c -o problem cc1: error: unrecognized command line option -Wsign-conversion
Re: Res: [c-prog] Re: integer promotions
--- Thomas Hruska wrote:
Try compiling your code as C++ and see if there
is a difference. C++ compilers tend to generate a lot more warnings as
the language is, generally-speaking, more strict.
[EMAIL PROTECTED] ~/programming/c++/problem
$ ls -la
total 10
drwxr-xr-x+ 2 root None 4096 Nov 27 22:47 .
drwxr-xr-x+ 11 root None 4096 Nov 27 22:35 ..
-rw-r--r-- 1 root None 69 Nov 27 22:37 Makefile
-rw-r--r-- 1 root None 261 Nov 27 22:46 problem.cpp
[EMAIL PROTECTED] ~/programming/c++/problem
$ cat problem.cpp
#include climits
#include iostream
using namespace std;
int main (void) {
unsigned short int a;
unsigned long long int b, c;
a = USHRT_MAX;
b = (a*a);
c = ((unsigned int)a*(unsigned int)a);
cout Why hex b != c ?\n;
return 0;
}
[EMAIL PROTECTED] ~/programming/c++/problem
$ cat Makefile
problem : problem.cpp
g++ -Wall -Wconversion problem.cpp -o problem
[EMAIL PROTECTED] ~/programming/c++/problem
$ make
g++ -Wall -Wconversion problem.cpp -o problem
[EMAIL PROTECTED] ~/programming/c++/problem
$ ./problem.exe
Why fffe0001 != fffe0001 ?
[c-prog] appliction crashing
Hi,
While I am trying to debug the following code , it is executing as expected.
But when trying to run with out debugging (debug version itself) , the
applicaton is crashing. May I know why is it so.
#include stdio.h
#include stdlib.h
struct Tree {
int data;
int priority;
struct Tree* lChild;
struct Tree* rChild;
};
struct Tree *root = NULL;
struct Tree *prev = NULL;
void heapInsert(struct Tree *tree, int key, int priority){
struct Tree *node = (struct Tree*)malloc(sizeof(struct Tree*));
node-data = key;
node-priority = priority;
node-lChild = NULL;
node-rChild = NULL;
if (root == NULL){
root = node;
} else {
struct Tree *dummy = (struct Tree*)malloc(sizeof(struct Tree*));
dummy = root;
if (dummy-priority = node-priority){
root = node;
root-lChild = dummy;
}
while (dummy-priority node-priority){
if (dummy-lChild == NULL){
dummy-lChild = node;
dummy = node;
}
else if (dummy-rChild == NULL) {
dummy-rChild = node;
dummy = node;
}
else {
prev = dummy;
dummy = dummy -lChild;
}
}
if (prev != NULL){
prev-lChild = node;
node-lChild = dummy;
prev = NULL;
}
/*printf(You are accessing the dummy root with pr %d\n,
dummy-priority);
printf(You are now trying to insert a second node.\n);
printf(First node still with priority %d, root-priority);*/
}
}
void treeTraversal(struct Tree * tree){
printf(Data: %d\n, tree-data);
printf(Priority: %d\n, tree-priority);
printf(LChild points to: %#x\n, tree-lChild);
printf(RChild points to: %#x\n, tree-rChild);
}
int main(void){
struct Tree *p = (struct Tree*)malloc(sizeof(struct Tree));
heapInsert(p,1,10);
heapInsert(p,2,2);
heapInsert(p,3,7);
heapInsert(p,4,9);
heapInsert(p,5,20);
heapInsert(p,6,5);
treeTraversal(root);
return 0;
}
GopiKrishna Komanduri
Software engineer
[EMAIL PROTECTED]
--- On Fri, 28/11/08, Pedro Izecksohn [EMAIL PROTECTED] wrote:
From: Pedro Izecksohn [EMAIL PROTECTED]
Subject: Re: Res: [c-prog] Re: integer promotions
To: c-prog@yahoogroups.com
Date: Friday, 28 November, 2008, 6:20 AM
--- Thomas Hruska wrote:
Try compiling your code as C++ and see if there
is a difference. C++ compilers tend to generate a lot more warnings as
the language is, generally-speaking, more strict.
[EMAIL PROTECTED] ~/programming/ c++/problem
$ ls -la
total 10
drwxr-xr-x+ 2 root None 4096 Nov 27 22:47 .
drwxr-xr-x+ 11 root None 4096 Nov 27 22:35 ..
-rw-r--r-- 1 root None 69 Nov 27 22:37 Makefile
-rw-r--r-- 1 root None 261 Nov 27 22:46 problem.cpp
[EMAIL PROTECTED] ~/programming/ c++/problem
$ cat problem.cpp
#include climits
#include iostream
using namespace std;
int main (void) {
unsigned short int a;
unsigned long long int b, c;
a = USHRT_MAX;
b = (a*a);
c = ((unsigned int)a*(unsigned int)a);
cout Why hex b != c ?\n;
return 0;
}
[EMAIL PROTECTED] ~/programming/ c++/problem
$ cat Makefile
problem : problem.cpp
g++ -Wall -Wconversion problem.cpp -o problem
[EMAIL PROTECTED] ~/programming/ c++/problem
$ make
g++ -Wall -Wconversion problem.cpp -o problem
[EMAIL PROTECTED] ~/programming/ c++/problem
$ ./problem.exe
Why fffe0001 != fffe0001 ?
Add more friends to your messenger and enjoy! Go to
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[Non-text portions of this message have been removed]
Re: Res: [c-prog] Re: integer promotions
On Thu 2008-11-27 16:50:55 UTC-0800, Pedro Izecksohn ([EMAIL PROTECTED]) wrote: [EMAIL PROTECTED] ~/programming/c++/problem $ ls -la total 10 drwxr-xr-x+ 2 root None 4096 Nov 27 22:47 . drwxr-xr-x+ 11 root None 4096 Nov 27 22:35 .. -rw-r--r-- 1 root None 69 Nov 27 22:37 Makefile It's never a good idea to be running as root...
