Visual C++ :: Using Wstring Converted From Char In DLL Class
Jun 17, 2013
I figured it out when I built a simple demo project. Problem arose because of trying to access a c-wrapper dll from the app class whereas the wrapper class had not been initialized there but rather in the main dialog class - so naturally it didn't work!!! Anyway, I've attached the demo for any who might be interested, but I regard the problem as resolved. Shows the value of building simple projects to isolate a problem. I failed to organize the order in which such a program initializes - I guess it's always App first, then MainFrame, then Doc and View (I think).
I am new to C++ and I have a two player word guessing game working well. However, I would like to be able to validate whether the word entered by player 1 is a completely alphabetic word using isalpha.
The error I am getting right now is as follows:
"error: array must be initialized with a brace-enclosed initializer char str[100]=hiddenwordtwo;"
Where col is a 'vec4' struct with a double[4] with values between 0 and 1 (this is checked and clamped elsewhere, and the output is safely within bounds). This is basically used to store rgb and intensity values.
Now, when I add a constant integer as a pixel value, i.e.:
buffer_rgb[i] = ((unsigned char)255;
Everything works as it should. However, when I use the above code, where col is different for every sample sent to the buffer, the resulting image becomes skewed in a weird way, as if the buffer writing is becoming offset as it goes.
You can see in the 'noskew' image all pixels are the same value, from just using an unchanging int to set them. It seems to work with any value between 0-255 but fails only when this value is pulled from my changing col array.
Whole function is here:
// adds sample to pixel. coordinates must be between (-1,1) void Frame::addSample(vec4 col, double contrib, double x, double y) { if (x < -1 || x >= 1 || y < -_aaspect || y >= _aaspect) {
I'm writing a class that has two constructors. However, I can't get them to work quite right. One constructor has a parameter of an int (with a default value of 0) and the other has a parameter of a C-style string.
First of all, are these function prototypes correct for the constructors?
MyInt(int n = 0);// first constructor, int param, default value 0 MyInt(const char * c);// second constructor, c-style string param
Both constructors work fine in some cases but don't work in all cases. Here are some potential calls to these functions that are supposed to work:
// These two work fine MyInt x(12345), y("9876543210123456789"), // The array assignment doesn't work when the value is negative // I'm not allowing negative numbers, but I want to create the object and assign the array to 0 r1(-1000),
[Code] .....
Here's the private data from the class (from the header file):
private: int currentSize, maxSize; char* digits;// Pointer to an array of digits
// Increase the size of digits array by 5 void Grow ();
I'm having trouble with passing a character array between functions of the same class. I have a function, buildGraph, that calls function getNextLine. The getNextLine essentially just retrieves the next line of an input file and stores it into a "char line[80]". However when I try to use "line" in my buildGraph function, it has nothing in it.
Here's my code:
Class #define NUMNODES 10 using namespace std; #pragma once class Prog3Graph
Why is the size of an empty class 1? Why is the class still one when I add a char member to the class?//using turbo c++ 3.0, yes I know I'm using a very old c++ compiler and software
Code: Error1error LNK2019: unresolved external symbol "public: __thiscall ReachTop<class Character>::ReachTop<class Character>(class Character *)" (??0?$ReachTop@VCharacter@@@@QAE@PAVCharacter@@@Z) referenced in function "void __cdecl `dynamic initializer for 'gReachTop''(void)" (??__EgReachTop@@YAXXZ)Main.objDecisionTest
I am writing a class which loads a bitmap image into a one dimension char* array.
This class has methods to allow for resampling and cropping the image before saving the bitmap image. It works perfectly for all images in which the width is divisible by 4. However when the width is not divisible by 4 the resulting bitmap is all mixed up.
I have spent much of the day googling this problem but to no avail. I know it is a problem with making sure the scanlines are DWORD aligned, and I believe I have done that correctly. I suspect that the problem is that I need to take the padding into account during the crop for loops but am lost to how to do this.
BTW: Coding on Linux using GCC
The following code is a cut down version from my bitmap class. I have removed methods which are not needed to make reading a little easier.
#include "BMP.h" // FIXME (nikki#1#): Portrait bug on images of specific sizes // TODO (nikki#1#): Memory leak checks // THIS METHOD WRITES A BITMAP FILE FROM THE CHAR ARRAY . bool BMP::saveBMP(string fileName, string *err) { FILE *filePtr;
#include "IMyIntData.h" class MyIntData : public CPMUnknown<IMyIntData> {
I need to know what this syntax means (including MyIntData in angular brackets after parent class name) where IMyIntData is the Interface from where MyIntData is derived.
My program is a basic MFC AppWizard (exe) created project in VC++ 6. In MainFrm.cpp, I am trying to access some user defined CMyView member functions. However when I try to do the standard procedure to get the CMyView pointer in MainFrm.cpp, I get the " ... 'CMyView' : undeclared identifier" error. To resolve this, I add " #include myView.h " at the top of MainFrm.h which then produces the following errors:
Code: myview.h(21) : error C2143: syntax error : missing ';' before '*' myview.h(21) : error C2501: 'CMyDoc' : missing storage-class or type specifiers myview.h(21) : error C2501: 'GetDocument' : missing storage-class or type specifiers
What do these errors mean? Is there a simple way to access CMyView member functions from CMainFrame?
I'm confused with this last [for] loop; How is ptr++ applied for non-integer value? Ptr is clearly a char, it comes from str, which reads string line from file.
I come from C# background, I have never met for...loop which irritates by using [somechar]++, not [someinteger]++; What is actually going on there?
Some other similar example might be:
Code: (iColor+(_parts[j]%length)*3),
where iColor is static unsigned char iColor[] array;
I would expect to see iColor[somevalue] + (_parts[j]%length)*3), but here in C++ I sometimes see that integer is being added directly to the array. What does it mean, what happens?
I have encountered a problem I can't see to solve. I want to access a function and can't seem to find the right combination to get me there. Here is what I am looking at:
CFoo1::CFoo2::GetStrDataC(int nRow) const
How do I call the GetStrDataC function from another class?
What is the programmers responsibility with respect to const char * returned by various functions, like the C++ string class c_str() function which returns a const char * to an c style string array? In VC++ I cannot delete a const char * which holds a string literal. Take the following code for example:
Code: void func() //a useless function with illustrative code { string s1("abcd"); string s2("efgh"); const char * cc1 = s1.c_str(); //c_str() returns a const char * c style string pointer s2.c_str(); //this returns a const char *, which must be allocated on the heap right? delete cc1; //produces run time error in Release mode in VC++ }
The problem with the above code snip is that space is allocated on the heap (or so I believe) for the const char *'s returned by the 2 calls to c_str(). The delete attempt fails and there is no opportunity to delete the space allocated by const char * because its not assigned to anything (however I see c_str() used this way extensively)
So, if I cannot delete a const char *, how does the memory get recovered? Perhaps the string objects s1 and s2 themselves have pointers to the items on the heap made by c_str() calls and they get deleted by the destructors of s1 and s2 when the function ends?
The characters show up in the list box as short unreadable characters. like it is chopped.
If i change to : Sendmessage(hndl, listboxupdate,0 , (LPARAM)&buf[15]);
Then I can see readable valid strings of up to 50 characters and then empty unreadable characters afterwards. I tried all kinds of things , including using CString, still did not work.
I only get like 500 chars, so I tryed a lot of different funcs until I finally realized that they reached the end of file "early" well it thinks that one of the chars in it is an end of file and it's located at the start. So I really don't know what to do with it because every func doesn't see the rest of the file at all.
Now i want to convert this into a unsigned char pointer.
unsigned char * pBMPHeaderData;
I already got the raw image data in another unsigned char buffer.
unsigned char* pRawBMPData;
Now i want to make a complete BMP image by adding the header info and raw data into a new unsigned char pointer. For this i need to convert the BITMAPINFO struct into a unsigned char *
I am using visual studio 2012.....in below code i m writing data in to a test.txt file but i dont know with which key file stop accepting char...i tried ctrl+z and ctrl+d but not working ....
