problem passing value

[dave]

void CalcPortGrossRe t(Funds tf[],int fsize,PortFolio tp,int cmonth)
{
int i=0;
float totgrossdlrval= 0;
char converter[10];
while(i<fsize){
tf[i].enddlrval=(tf[i].dlrval*(tf[i].ret[cmonth]/100.0)+tf[i].dlrval);
totgrossdlrval+ =tf[i].enddlrval;
i++;
}
tp.grossenddlrv al=totgrossdlrv al;
tp.ret[cmonth]=(tp.grossenddl rval-tp.grossdlrval)/tp.grossdlrval;
sprintf(convert er,"%.5f",tp.re t[cmonth]);
MessageBox(NULL ,"Monthly return for portfolio is "
+ (CString)conver ter,"C++ Debugger",NULL) ;

}

after CalcPortGrossRe t is called with
CalcPortGrossRe t(thefunds,3,th eport,im);
and returns,
theport.grossen ddlrval has garbage in it.

While in function tp.grossenddlrv al is correct.
tp.grossenddlrv al is a float.
theport is defined in the calling function.
whats happening?

thanks

[Dan Cernat]

dave wrote:

void CalcPortGrossRe t(Funds tf[],int fsize,PortFolio tp,int cmonth)
{
int i=0;
float totgrossdlrval= 0;
char converter[10];
while(i<fsize){
tf[i].enddlrval=(tf[i].dlrval*(tf[i].ret[cmonth]/100.0)+tf[i].dlrval);
totgrossdlrval+ =tf[i].enddlrval;
i++;
}
tp.grossenddlrv al=totgrossdlrv al;
tp.ret[cmonth]=(tp.grossenddl rval-tp.grossdlrval)/tp.grossdlrval;
sprintf(convert er,"%.5f",tp.re t[cmonth]);
MessageBox(NULL ,"Monthly return for portfolio is "
+ (CString)conver ter,"C++ Debugger",NULL) ;

}

after CalcPortGrossRe t is called with
CalcPortGrossRe t(thefunds,3,th eport,im);
and returns,
theport.grossen ddlrval has garbage in it.

While in function tp.grossenddlrv al is correct.
tp.grossenddlrv al is a float.
theport is defined in the calling function.
whats happening?

thanks

tp is an object. Does it have the proper copy constructor?

/dan

[Alf P. Steinbach]

* dave:

void CalcPortGrossRe t(Funds tf[],int fsize,PortFolio tp,int cmonth)
{
int i=0;
float totgrossdlrval= 0;
char converter[10];
while(i<fsize){
tf[i].enddlrval=(tf[i].dlrval*(tf[i].ret[cmonth]/100.0)+tf[i].dlrval);
Possible buffer overrun.
totgrossdlrval+ =tf[i].enddlrval;
i++;
}
tp.grossenddlrv al=totgrossdlrv al;
'tp' is passed by value into this function, this should have no effect.

tp.ret[cmonth]=(tp.grossenddl rval-tp.grossdlrval)/tp.grossdlrval;
Possible buffer overrun.

In addition, for this to have any effect when there's no buffer overrun,
'tp.ret' would need to be a pointer.

Also, it's rather gross using public members...

sprintf(convert er,"%.5f",tp.re t[cmonth]);
Possible buffer overrun.

MessageBox(NULL ,"Monthly return for portfolio is "
+ (CString)conver ter,"C++ Debugger",NULL) ;

}

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

[dave]

I think I must pass as a reference to change values, ret changed because ret
is defined as an array of floats so...
it is automatically passed by reference.
I thought classes where always passed by reference?
Is this true ?
I'm a little confused.
Is this true ?

thanks

"dave" <sp*****@hotmai l.com> wrote in message
news:iu******** *********@bigne ws5.bellsouth.n et...

void CalcPortGrossRe t(Funds tf[],int fsize,PortFolio tp,int cmonth)
{
int i=0;
float totgrossdlrval= 0;
char converter[10];
while(i<fsize){
tf[i].enddlrval=(tf[i].dlrval*(tf[i].ret[cmonth]/100.0)+tf[i].dlrval);
totgrossdlrval+ =tf[i].enddlrval;
i++;
}
tp.grossenddlrv al=totgrossdlrv al;
tp.ret[cmonth]=(tp.grossenddl rval-tp.grossdlrval)/tp.grossdlrval;
sprintf(convert er,"%.5f",tp.re t[cmonth]);
MessageBox(NULL ,"Monthly return for portfolio is "
+ (CString)conver ter,"C++ Debugger",NULL) ;

}

after CalcPortGrossRe t is called with
CalcPortGrossRe t(thefunds,3,th eport,im);
and returns,
theport.grossen ddlrval has garbage in it.

While in function tp.grossenddlrv al is correct.
tp.grossenddlrv al is a float.
theport is defined in the calling function.
whats happening?

thanks

[Dan Cernat]

don't toppost.
dave wrote:

I think I must pass as a reference to change values, ret changed because ret
is defined as an array of floats so...
it is automatically passed by reference.
I thought classes where always passed by reference? C++ is not Java or C# Is this true ? no, it is not true.
I'm a little confused.
Is this true ?

[snip]

this makes me ask again: does your class has a proper copy constructor?

or pass by reference.

/dan

[AnonMail2005]

Instances of classes and built in types are always passed by value.
Arrays, of course, are passed as a pointer to the first element of the
array. If you want to pass by reference you need to explicitly say so.

[dave]

"Dan Cernat" <dc*****@excite .com> wrote in message
news:11******** **************@ f14g2000cwb.goo glegroups.com.. .

dave wrote:

void CalcPortGrossRe t(Funds tf[],int fsize,PortFolio tp,int cmonth)
{
int i=0;
float totgrossdlrval= 0;
char converter[10];
while(i<fsize){
tf[i].enddlrval=(tf[i].dlrval*(tf[i].ret[cmonth]/100.0)+tf[i].dlrval);
totgrossdlrval+ =tf[i].enddlrval;
i++;
}
tp.grossenddlrv al=totgrossdlrv al;
tp.ret[cmonth]=(tp.grossenddl rval-tp.grossdlrval)/tp.grossdlrval;
sprintf(convert er,"%.5f",tp.re t[cmonth]);
MessageBox(NULL ,"Monthly return for portfolio is "
+ (CString)conver ter,"C++ Debugger",NULL) ;

}

after CalcPortGrossRe t is called with
CalcPortGrossRe t(thefunds,3,th eport,im);
and returns,
theport.grossen ddlrval has garbage in it.

While in function tp.grossenddlrv al is correct.
tp.grossenddlrv al is a float.
theport is defined in the calling function.
whats happening?

thanks

tp is an object. Does it have the proper copy constructor?

/dan

no copy constructor isnt't there a c++ defualt?

[Dan Cernat]

dave wrote:

"Dan Cernat" <dc*****@excite .com> wrote in message
news:11******** **************@ f14g2000cwb.goo glegroups.com.. .

dave wrote:

void CalcPortGrossRe t(Funds tf[],int fsize,PortFolio tp,int cmonth)
{
int i=0;
float totgrossdlrval= 0;
char converter[10];
while(i<fsize){
tf[i].enddlrval=(tf[i].dlrval*(tf[i].ret[cmonth]/100.0)+tf[i].dlrval);
totgrossdlrval+ =tf[i].enddlrval;
i++;
}
tp.grossenddlrv al=totgrossdlrv al;
tp.ret[cmonth]=(tp.grossenddl rval-tp.grossdlrval)/tp.grossdlrval;
sprintf(convert er,"%.5f",tp.re t[cmonth]);
MessageBox(NULL ,"Monthly return for portfolio is "
+ (CString)conver ter,"C++ Debugger",NULL) ;

}

after CalcPortGrossRe t is called with
CalcPortGrossRe t(thefunds,3,th eport,im);
and returns,
theport.grossen ddlrval has garbage in it.

While in function tp.grossenddlrv al is correct.
tp.grossenddlrv al is a float.
theport is defined in the calling function.
whats happening?

thanks

tp is an object. Does it have the proper copy constructor?

/dan

no copy constructor isnt't there a c++ defualt?

if you don't supply a copy constructor, the compiler will generate one
for you. That doesnt mean that the compiler-generated copy constructor
always does the right thing. it just copies member by member the
original object. If one of the members is a pointer, it will copy the
pointer so you will and up with two objects pointing to the same memory
area. check it out.

however, post the minimal compilable amount of code that shows your
problem if you want more.

/dan

[Greg Comeau]

In article <11************ **********@g47g 2000cwa.googleg roups.com>,
<An**********@g mail.com> wrote:

Instances of classes and built in types are always passed by value.
Arrays, of course, are passed as a pointer to the first element of the
array. If you want to pass by reference you need to explicitly say so.

<nitpick on>
Meaning that for your first sentence to be true, the last one can't be :)
--
Greg Comeau / Celebrating 20 years of Comeauity!
Comeau C/C++ ONLINE ==> http://www.comeaucomputing.com/tryitout
World Class Compilers: Breathtaking C++, Amazing C99, Fabulous C90.
Comeau C/C++ with Dinkumware's Libraries... Have you tried it?

[dave]

Why would a copy constructor cause the behavior I require, in this situation
isn't
passing by ref may only option?
"Dan Cernat" <dc*****@excite .com> wrote in message
news:11******** **************@ o13g2000cwo.goo glegroups.com.. .

don't toppost.
dave wrote:

I think I must pass as a reference to change values, ret changed because ret is defined as an array of floats so...
it is automatically passed by reference.
I thought classes where always passed by reference?

C++ is not Java or C#

Is this true ?

no, it is not true.

I'm a little confused.
Is this true ?

[snip]

this makes me ask again: does your class has a proper copy constructor?

or pass by reference.

/dan