C++ :: Name Resolution Not Working As Expected

Apr 23, 2013

I have a global var (m) with an initial value 5.

I have a template class (A) that derives from a either a base class that has a member (_A1.m) or not (_A0), based upon it's template parameter. class (A) has a member function (fn) returns the value of (m) as it understands what (m) is.

However, this gives different results compared with a non-template class in a similar scenario. I'm expecting that if derived from _A1, that m should be taken from the base class scope and if derived from _A0, it should be taken from the global one.

Here is the code for your amusement:

int m = 5;
class _A0 {
public:
_A0(int) {

[Code] ....

This compiled using g++ 4.5.3 and 4.6.3 with the same results:
Global value of m is: 5
B0 class has no internal m member. Object resolves m internally with value 5
B1 class has internal m member. Object resolves m internally with value 3
A<_A0> class has no internal m member. Object resolves m internally with value 5
A<_A1> class has internal m member. Object resolves m internally with value 5

View 2 Replies


ADVERTISEMENT

C++ :: Average Calculation Function Not Working As Expected To

Dec 16, 2013

[URL] ....

My calculation function will not work like i wanted it to. It gives me 0 or a crazy number.

this is the function here:
the entire code is on the link:

double calculations(data&avgs) //Calculates the students grade into a final grade
{
int avg1;
int avg2;
int avg3;
int lab1;

[Code] ....

View 12 Replies View Related

Visual C++ :: OnSize Handler Not Working As Expected

Nov 6, 2013

I keep having problems with CMFCPropertySheets. I now have it embedded in a resizable dialog and the property sheet and page gets resized when dialog is resized all that is working fine.

Problem is OnSize is being called when the dialog is being resized NOT when it has finished resizing so the values reported in cx and cy is the old size not the size AFTER resizing. What could be causing this? Isn't OnSize call AFTER the size has been changed and OnSizing called WHILE the size is being changed?

I have a list control that needs to take up full rect in each page and when the dialog is maximized it stays at previous size even though the sheet and page have both maximized as they should.

I ran a trace on the OnSize even for both the sheet and page and OnSize is being called during the sizing and not after it has already been sized like it is supposed to.

View 6 Replies View Related

C++ :: Scope Resolution Operator?

Feb 21, 2013

I have done alot of googling for the scope resolution operator and Ive gained a bit of an understanding as to what it does i know it can distinguish between global and local variables, but I see it used to access methods/members of classes such as this example, why not just use a dot instead to access it?:

sql:: Driver *driver;

Why is the scope resolution operator being used here?

View 11 Replies View Related

C/C++ :: Setting Resolution On Screen

Mar 29, 2015

Just reading some code and come across a section where its setting the resolution on a screen

so like

image->sizeX=640;
image->sizeY = 480;
size = image->sizeX * image->sizeY *3;
float sizeLog = ceil(log((float)image->sizeX) / log(2.F)));

So yea, my understanding of this code is that firstly there is member access and that a resolution is being set.

And then its like 640 * 480 * 3

and then the log of 640 *480*3 ...being divided by something else and being rounded up by ceil

is this the right way to look at it?

and also what is the log(2.F) - i don't really understand that.

View 3 Replies View Related

C++ :: Variadic Templates And Overload Resolution

Jan 2, 2014

I'm trying to learn how to use variadic templates, and I decided a great example would be serializing a series of types into a stringstream:

Code:
// Send a fully constructed message.
virtual void send(ostringstream &msg) = 0;
// Construct a message from the arguments and send it.
// This is the usual entry point.
template <typename ...Args>
void send(Args ...args {

[Code] ....

This works fine, so far as I can tell. However, I decided to see if I could specialize the way certain types are serialized. I tried using a Google Protocol Buffer object as an example, and added this:

Code:
// Handle a protocol buffer type while constructing a message.
template <typename ...Args>
void send(ostringstream &msg,
const google::protobuf::MessageLite &protobuf, Args ...args) {
std::string msg_str = protobuf.SerializeAsString();
msg << msg_str;
send(msg,args...);
}

I would expect this overload to be preferred over the generic T overload when a protobuf object (which always inherits from MessageLite) is passed into send() anywhere in the list. However, this is not happening. I am getting an error message to the effect that << doesn't know how to deal with my concrete type, pointing at the T overload.

View 4 Replies View Related

Visual C++ :: MFC Dialog Clipping Off In Low Resolution

Mar 25, 2013

I have an mfc dialog of size 1280 X 1024 and when i change the resolution to 800 X 600, after adding scroll bar, it don't show the entire dialog contents, Seems like it clips the 800 X 600 portion.

I have handled VScroll and HScroll. It works fine for higher resolutions!

View 1 Replies View Related

Visual C++ :: How To Find Printer Resolution From GetDeviceCaps

Dec 6, 2012

I have written a program to capture signal from machine and display it on screen in the form of sinosoidal wave. I have print buffer for 256 X 400 pixel strip chart. This prints fine if I set page size A4 and resolution 600 DPI. If anyone changes print parameters , there is problem. I can resize the printer buffer and interpolate the stored signal.

My problem is , how to find the printer resolution from GetDeviceCaps ? how to know the Print Type Normal / Draft etc in mFC.

View 2 Replies View Related

C++ :: VGA Resolution Limit With 1bpp Mono Graphics Modes?

Aug 25, 2014

What is the limit of a VGA with 256k VRAM, running 1bpp monochrome graphics? How high can the display resolution go?

View 3 Replies View Related

C++ :: Template Function Overloading Resolution Different In Visual Studio And GCC

Jun 13, 2014

I stumbled upon an unexpected difference between GCC and VisualStudio: Different overloaded functions are called in the following example:

// -------- can assume this is located in 'tool.h' file --------------
// Fwd declaration support foo( const int& ) gets called as expected by both compilers
// void foo( const int& n );

template< typename T >
void foo( const T& n ) {

[Code] ....

What happens: I expected that by calling bar(1) compiler will notice both versions of foo() and call the best match, in this case foo(const int&). That is not the case.

Note that overloaded foo(const int&) is below bar(). It seems that at that point GCC does not see overloaded version, and happily calls template version. Visual studio on the other hand has no problem finding them both.

If I introduce a forward declaration of foo( const int& ) before bar(), both compilers call that version correctly. Unfortunately, that is not a solution for my problem here.

Template version is part of a library while overloaded is part of the user code. Both would be located in different (header) files and I would not like to impose #include order to the users or to be dependant on it.

View 2 Replies View Related

Visual C++ :: Free Image Library That Handle PNG Resolution

Mar 14, 2013

Need a free image library that can handle png xresolution and yresolution. I need it to be compatible with visual studio 6.0

View 1 Replies View Related

C/C++ :: Expected Initializer Before Int

Jan 21, 2015

#include <iostream>
int ival1
int ival2=1
int summe
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
int main() {

[Code] .....

If I compile it I've got these errors

[Error] expected initializer before 'int'

recipe for target 'rechnen.o' failed

View 14 Replies View Related

C++ :: ATM - Expected Primary Expression Before Else

Mar 29, 2014

I keep getting an error here and cant quite figure out why,

Code:
else if (mainMenu == 3){
cout << "Please make a selection" << endl
<< " 1) Withdraw from account" << endl
<< " 3) Back to main menu" << endl;
cin >> withdrawMenu;

if (withdrawMenu == 1){

[Code] ....

View 1 Replies View Related

C :: Expected Expression Before Token

Jun 18, 2014

I wrote a program, that generates 20 random integers, and stores them in an array. Then I decided, to build more functions to it, i.e why not have it to display the lowest integer of an array. I created my function,

Code:
int minValue( int field[ ] )

and got my code in side, which (technically) works. In my main() function I'm calling

Code:
printf( "The smallest value of an array is: %d
", minValue( field[] ) );

and I'm getting an error trying to compile it.

Code:
randomArray.c:62:74: error: expected expression before ']' token
printf( "The smallest value of an array is: %d
", minValue( field[] ) );

View 2 Replies View Related

C++ :: Expected Primary Expression Before INT

May 26, 2014

This is what i have example code in c++:

#include <iostream>
class Foo{
public:
void bar(){
std::cout << "Hello" << std::endl;

[Code] ....

After compiling it is giving error as :
foo.cpp: In function ‘int Foo_max(Foo*)’:
foo.cpp:26:37: error: expected primary-expression before ‘int’
foo.cpp:26:46: error: expected primary-expression before ‘int’

View 6 Replies View Related

C++ :: Do While Loop - Expected Unqualified ID

Jan 21, 2014

This first Dowhile loop is saying "expected unqualified-id" at the do and while parts. What does that mean

do {
do {
do {
std::cout << "Give me a test result or grade from 0 to 100 for class"<< 1 << std::endl;
std::cin >> mathaverage[mathtestcount];
loopresult=1;

[Code] .....

View 2 Replies View Related

C++ :: Error - Expected Unqualified ID

Dec 2, 2014

I can't figure out this error.

#include <iostream>
using namespace std;
bool isPrime(int number); {
primeNumber = isPrime(number);

[Code] ....

View 2 Replies View Related

C++ :: Destructors Being Called More Than Expected?

May 20, 2013

In this code:

#pragma once
#include <iostream>
class CBox // Derived class {
public:
// Constructor
explicit CBox(double lv = 1.0, double wv = 1.0, double hv = 1.0) : m_Length(lv), m_Width(wv), m_Height(hv){}

[Code] .....

Before the program ends, at return 0;

I would expect the CBox destructor to be called 3 times but it is being called 6 times? Why? Also in this code:

#pragma once
#include <iostream>
class CBox // Derived class {
public:
// Constructor
explicit CBox(double lv = 1.0, double wv = 1.0, double hv = 1.0) : m_Length(lv), m_Width(wv), m_Height(hv){}

[Code] .....

Why is the destructor called 3 times? When have you really destroyed a CBox? Doesnt emplace only create it and store it, then thats it?

[URL] .....

For pushback:

void push_back(value_type&& _Val)
{// insert by moving into element at end
if (_Inside(_STD addressof(_Val)))
{// push back an element
size_type _Idx = _STD addressof(_Val) - this->_Myfirst;

[Code] .....

View 12 Replies View Related

C :: Float Variable Increases More Than Expected

Sep 14, 2014

I just wrote the following simple program:

Code:
#include <stdio.h>
#include <math.h>
int main(void) {
float fx, x;

[Code] ....

The output increases x by 0.1 as expected until x=1.5. After that x becomes 1.600001 and not 1.6 as expected.

View 9 Replies View Related

C++ ::  Expected Identifier With Numeric Limits

Aug 22, 2014

I'm trying to perform a simple input operation, and check to make sure that whatever the user input is a valid input (is within data type bounds, is correct data type...). But when I get to ignoring the input, I keep getting an error.

unsigned short num;
while (true) {
std::cin >> num;
if (std::cin.fail()) {
num = 1;

[Code] ....

I don't fully understand why this error is here.

View 6 Replies View Related

C/C++ :: Error / Expected Initializer Before String

Nov 15, 2014

I'm working on a school project learning C++. I'm running into an error I can't seem to find the answer for (see topic title).

main.cpp
#include <iostream>
#include <string>
#include "Signature.h"
#include "Genome.h"
using namespace std;
// Calling Function
int main() {
Signature Sig1; // Create Signature object
Genome gString1; // Create Genome object

[code]....

View 1 Replies View Related

C/C++ :: Error - Expected Unqualified-id At End Of Input?

Apr 3, 2014

#include<iostream.h>
#include<stdio.h>
#include<conio.h>
using namespace std;
class CV {
    public:
    char name; 
    char qualfctn;

[Code]....

View 1 Replies View Related

C/C++ :: Expected Declaration Specifier In For Loop?

Mar 1, 2015

#include <stdio.h>
#include <math.h>
main() {
int n;
int k;
int j;
//gets user input for length of string
printf("Enter the value of n:");
scanf("%d", &n);

[code]......

When I compile my code I get an error saying that I need declaration specifiers in my is_prime subroutine in the for loop.

Here is the line of code it references.

for(j = 2; j < k; j++)

View 2 Replies View Related

C++ :: No Constructor Could Take Source Type Or Constructor Overload Resolution Was Ambiguous

Mar 1, 2014

i am writing this bank accounts program using structures. i haven't implemented the function before that i want to check if the data is being read and printed. When i build and run the program in visual studio it gives me the following error. "No constructor could take the source type, or constructor overload resolution was ambiguous". Now whats wrong in this program?

/* Bank Accounts Program */
#include <iostream>
#include <string>
#include <fstream>
#include <cstdlib>//needed to use system() function
using namespace std;
const int MAX_NUM = 50;
struct Name{

[code]....

View 1 Replies View Related

C :: Stack Overflow - Expected Expression Error

Sep 10, 2013

I'm pretty new to C, and keep getting an error. Basically I'm trying to convert a ppm image to all red. Here is my code that I can't get to work:

Code:
change(pixel_t *PIXEL, &w, &h,pixel_t *buffer);

And here is the beginning of my convert function:

Code:
void change(pixel_t *pixel, int w, int h, pixel_t *buffer) {

int average, sum;
int i;
pixel_t *pointer;

Everything else works fine. I keep getting an error when I call the convert function. It says "expected expression before pixel_t" and "too few arguments to function "change". I know that everything else in the main is working.

View 3 Replies View Related

C :: GSL And OpenMP - Getting Random Numbers That Are Out Of Expected Range

May 2, 2013

I am trying to parallelize some of my code with OpenMP. When I switch to using multiple threads I start getting random numbers that are out of the expected range.

Here is a small example:

Code:
#include <stdio.h>
#include </usr/local/include/gsl/gsl_rng.h>
#include </usr/local/include/gsl/gsl_randist.h>
int main() {
int mySeed=0;
const gsl_rng_type *T;
T = gsl_rng_ranlxs2;
gsl_rng *r_1 ;

[Code] .....

gsl_rng_uniform should only output number in the range [0,1) but with multiple threads it outputs larger number as well.

View 2 Replies View Related







Copyrights 2005-15 www.BigResource.com, All rights reserved