A quick clarification on virtual methods after reading Jumping int C++ by Alex Allain. If a user wanted to extend a class from someone elses library and override its methods that do not contain virtual methods; how would one call the overridden class if it is referred to by its super type
in other words how would someone override a method from someone elses library that does not have virtual keywords.
Code: #include <iostream> #include <string> using namespace std; class test{ public: virtual void ola() {
[Code] .....
Like you see, i don't re-declare the 'ola' function in 'test1' class, only in 'test' class. The compiler tell me the 'ola' isn't member of 'test1'. in 'test' i put it 'virtual', but forgetting that, how can i override it without re-declare it?
I need to override a few methods in FILE class so i defined few methods as
EnCrpt * fp; fp * fopen(const char * filename, const char * mode); int fwrite(const void * p,int length,int readLenth,FILE * fpp = NULL); int fread(void * p,int length,int readLenth,FILE * fpp = NULL); int fseek(FILE * fpp = NULL,long offset, int whence); long ftell(FILE * fpp = NULL); int feof(FILE * fpp = NULL); int fflush(FILE * fpp = NULL); int fclose(FILE * fpp = NULL);
I will call fread method in my encrypted file class .. similar to other methods.. is this correct ? can NULL file pointer create issue ?
Because i have so many place where FILE class called i don't want to change everywhere to call encrypted file class so i am override these methods to encrypted file class instead of standrd FILE class
output.displayHeader() must execute before the inherited from ostream (cout) executes streaming data, or bad things happen. It's of course not as simple as in the example below, and I need to make sure displayHeader() is never missed.
I'm thinking I need to override the "<<" operator, having my own function call displayHeader(), then call the base (cout) "<<" operator. What's the proper syntax for doing this?
I can't call displayHeader() in the constructor, and I can't call it right after the object is defined. There are exception case scenarios where displayHeader() must not be called, and other things must happen instead.
I'm aware this will result in many redundant bool comparisons versus the way I'm doing it now, and I'm perfectly OK with that.
Code: #include <iostream> using namespace std; class myOutput : public ostream { public: myOutput() : ostream(cout.rdbuf()) {
I've been trying for more than one month to access a method found in a library called libcocosnas_static.a. I'm using Cocos2d-X version 2.0.4. The library has been used many times by my company to make games using cocos2d-1.0.1-x-0.12.0 without any problem.
This is what I've done: 1- I added the include paths of the library to both eclipse and Android.mk 2- Included the .h file using #include "NASPlatformUtil.h" 3- Added the libcocosnas_static.a file to the proj.androidobjlocalarmeabi folder 4- Added "LOCAL_WHOLE_STATIC_LIBRARIES += cocosnas_static" to the Android.mk file 5- Called the function using: NASPlatformUtil:: openUrl("http://xxx.xxx.com/");
I can right click on the function, click Open Declaration and get it without any problem, but the compiler keeps on giving me that dreaded error...
I'm overriding OnNcPaint to do my own caption painting (in a dialog box). If I call "Default" before I do my painting, the default caption and borders remain (as if I'm not painting at all). If I comment out my call to "Default", my caption looks great, but I get no menu bar (I have a menu on the dialog). If I call "DrawMenu" before or after painting, the dialog is all screwed up (and there is no painting in the nonclient area).
Im supose to use <>bool removeTile(char, int, int, char[])<> to do this "function that takes in the choice (D or S) and the two dice numbers and the board as input arguments. When the move is legal and the tile is available for removal, it removes the tile according to the choice by marking the tile as ‘X’. Returns true if the move is successful."
My issue is regardless of which date I input its always defaulting to the values I have set in my constructor in my implementation file in the else statement. So the values always default to 3/15/2006 I think its something to do with the logic in my bool function but I may be incorrect.
header //date.h header #include <iostream> #include <string> using namespace std;
enum DateFormat {numeric, standard, alternative}; const int MIN_YEAR = 1900; const int MAX_YEAR = 2015;
How to get my data from the file and output, but now I am having trouble with my acceleration function. Right now, I have the acceleration function commented out and the output for acceleration at the bottom because if I try to run the program with them in it the program stops working. working with acceleration calculations and then finally outputting that acceleration.
//Program that reads the time and vertical velocity data and then calculates things from it
I have a question similar to the one here: [URL] .....
The main difference is I would like to pass a method of derived class as a parameter to some other method in its template base class.
template <typename BaseType> class Base { public: typedef void (Base::*Callback)(int A);
[Code] .....
The above is an example which does not compile. My compiler complains that the two BaseMethod() calls in DerivedMethod() are invalid uses of non-static member function.
Is this not possible to do, or is my syntax simply wrong? All I want is to be able to pass as an an argument to a method in the base class from the derived class some callback as a variable for the base class to invoke later.
I am again a bit confused with bool since we have not used them much. I understand it is suppose to return a true or false value that is represented by 0 and 1. so I have these two bool's
cout << "Is this a right triangle: " << t2.isRight() << endl; cout << "is this a Triangle: " << t2.isTriangle() << endl;
and i get this "Is this a right triangle: " 0 "Is this a triangle: " 1
Which i know is correct but I want to replace the 1 and 0 with my own string but the things iv tried tweaking with has not worked.
Also in the file attached has some requirements from my teacher but i was confused at the second last one, --- bool isEqual(Triangle &other) and it says return true if triangles are equal and false if triangles are not.
I dont know if this is just simply if one triangle equals another (however you determine that) or if its for the two bool's, isTriangle() and isRight() or what.
I have a piece of code in C with header files included. I run it on Mac OS X Maverick with XCode 4.6.2 installed. GCC is also installed. Note that Command Line Tools in XCode are already installed.
When I compile it, the error I receive says something like this:
add.c:1:19: error: stdio.h: No such file or directory add.c:2:20: error: stdlib.h: No such file or directory add.c:3:20: error: unistd.h: No such file or directory
However when I run it on Ubuntu, it compiles without a problem.What to do?
I am working on a couple C++ projectsfor my class. On one of my projects I get this error "identifier not found" for maximumValue. here is the code that I have done. I have got almost all the code from my text book..
// Three numbers.cpp : Defines the entry point for the console application.//
#include "stdafx.h" #include <iostream> using namespace std; int main() { // demonstrate maximum int value int int1, int2, int3;
I have counted my braces and it look to be correct but I am seeing double.. I am getting the "end of file found before the left brace.. do I have one in an incorrect place?
#include <iostream> #include <string> #include <fstream> #include<cmath> using namespace std;