C++ :: Pass Parameters - Invalid Use Of Void Expression
Jun 6, 2013
I am trying to run a void function and pass parameters to it on a thread using std::thread. However, I keep getting compile errors. When I can get it to compile it does not create the file. Here is my code:
I've created a class that works with vectors doing various calculations and what not. I have overloaded operators that I've created outside of the main in separate header and class files. Ive tested them and the overloaded operators work correctly when I paste them into a the main file but when I have them defined in the other class files and I try to access them in the main class I get an error saying invalid operands to a binary expression. I also have other classes with overloaded operators that work just fine in the main class so I'm not sure what I did wrong here?
This is how I have my header set up, the definitions to these are in a separate class file which I don't think I need to include considering I have them tested and working so I don't think that's the problem (correct me if I'm wrong).
#include "Name of vector class" int main(){ vector<float> vR, v1, v2; v1.push_back('some value'); ... v2.push_back('some value'); ... vR = v1 + v2; // Invalid operands here return 0; }
And like I said, I have other classes with overloaded operators set up the same way which work fine being implemented the way I have these, so I'm not sure where the problem is at.
How can I pass a function as a parameter? I have a class that I'm trying to reuse and one of the methods in this class need to take three parameters, two ints and a function. In other words I want to be able to call a custom function every time this method is invoked when used in other classes. The function I want to call will not return any values, its a void function.
In my Class:
void Utility::someFunction(int var1, int var2, void customFunction) { int num1 = var1; int num2 = var2;
I'm creating simple console application using Code::Blocks to allow me to pass parameters from other application to replace string within text/registry file before execute the registry merge. Passing parameters to console already success. Now I only have problem with reading file. Example of first line in the registry file is as below.
Windows Registry Editor Version 5.00
However when read into string and output to console using 'cout', it will be show as below with spaces in between.
W i n d o w s R e g i s t r y E d i t o r V e r s i o n 5 . 0 0
I'm trying to write a simple Delegate class with a Bind() and Invoke() function. For now it only needs to support a void class function with no parameters. I've searched around and found quite a few exmaples, though, those class are heavily templated and I lose track trying to simplify it.
So far my code is following:
Code: #include <windows.h> class Test { public: void DoSomething() { MessageBox(NULL, L"Test::DoSomething!", NULL, 0);
[Code] ....
The part I am having difficulty with is assigning &Test::DoSomething to the m_Callback variable.
&tObject::DoSomething works, yet _Callback which I pass &Test::DoSomething to does not work.
I'm trying to pass 2 arrays into a void funtion, and return values to one function.
this is the the program I'm working with, after I'm done I have to split it into 3 files, a header, a main, and a separate cpp file for the functions to live in.
#include <iostream> using namespace std; void processArrary(int numberCount[], int Numbers[], int intnumberSize, int numberCountSize); int main() { int Scores[26] = {76, 89, 150, 135, 200, 76, 12, 100, 150, 28, 178, 189, 167, 200, 175, 150, 87, 99, 129, 149, 176, 200, 87, 35, 157, 189}; int numberCount[8] = { 0 };
[code]...
The goal of this program is to separate and count the groups of numbers then output the amount of numbers in each group. Near as I can tell, everthing should work, but I'm getting all zeros to be displayed in each group.
I've been given an assignment with the below questions.
1. What is the difference between pass by reference & pass by pointers?
2. What is the use of the initialization list in the constructor?
3. What is meant by a reference & its advantage?
4. Class has a reference, pointer and a const. Is it possible to write the copy constructor & assignment operator overloading funciton? how? ( Since reference is there, I'm not sure on how to write for it)
5. Example for a variable decleration and definition? (I know for function but for variable don kw how)
6. static and const static what is the difference??
i think i understand both concept. i know that pass by value is that the function receiving those values makes actually a copy of those parameters. Passing by reference makes the variable in the main function to actually see those changes in the other function, instead of a copy, and apply them to the variable in the main function. my question is, why would i pass it by reference if i just can make a return type function.
After looking online for a string replace function in C and finding so many examples that go through the entire string twice. First round to find how number of occurances of substitute in string, using that to malloc for a new string to include additional space for replace, then going through the search string again to get all but what's to be substituted out. I feel it's kind of silly to go through the string twice. Therefore, I'm trying to implement my own string replace, that only searches through the string for what's to be substituted, once.
Here is the same code, but with execution + some syntax highlighting: Ideone.com | Online C Compiler & Debugging Tool..It works great, until it gets to grabbing whatever remains in the search string after the last found sub. The realloc throws a runtime error:
Aborted From my understanding, this is from me going outside of the bounds of the heap and using memory I haven't allocated, or using a free'd pointer. I'm not seeing where either of these are happening in my code, and was wondering what the best way to go about figuring out where the error exactly occurs.
The exercise consists on 3 procedures. We get the information from a .txt like these:
01/03/2011 A 02/03/2011 F 03/03/2011 C 04/03/2011 T (...)
Simulating a Videoclub database where the letters stand for the type of movie (A=Action, T=Terror, C=Comedy, ...) and the dates they were rented.
a) How many movies from one specific genre have been rented more than 'n' times? The genre and the value 'n' must be entered by the user.
b) How many movies and which genres belong to a certain date? The date must be entered by the user.
c) Print a list that shows the number of times a movie from each genre has been rented.
So far this is what I've got:
Code: #include <stdio.h> #include <stdlib.h> #include <string.h> #define MAX 100
typedef struct { int dia,mes, any; char genere;
[Code] ....
But right now, my main problem is that I can't even debug because i get an error in line 97 --> while (llista[i][j] != EOF) <-- saying "invalid operands to binary != (have 'lloguer' and 'int').
I've tried to cast (int) before "llista[i][j]" but it says that I'm already supposed to get an integer from that.
I catch an exception and want to log it on the console. This works as exepcted, but Valgrind shows me a set of invalid reads.
Here the code of the catch-block:
} catch(HGL::IOException &e) { logError(e); }
The signature of the logDebug is: BasicLogger &operator<<(const std::exception &e);
Now valgrind shows me 4 errors like that:
==20943== Invalid read of size 1 ==20943== at 0x402C658: strlen (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so) ==20943== by 0x41554DD: std::basic_ostream<wchar_t, std::char_traits<wchar_t> >& std::operator<< <wchar_t, std::char_traits<wchar_t> >(std::basic_ostream<wchar_t, std::char_traits<wchar_t> >&, char const*) (in /usr/lib/i386-linux-gnu/libstdc++.so.6.0.16)
[Code] .....
Generally I dislike invalid read in my code, even if they are harmless like in that case.
If I don't pass a reference, but a copy of the exception, I don't get this invalid reads, but also loose all information, because of the implicit upcasting.
Why I get the illegal read, resp. why std::wstring is deleting it on the way to the <<-operator?
Basically the whole purpose of this program is to prompt the user to use a calculator. Choices 1-6 are valid, but I want to set it up where selecting any other number outside of 1-6 to be Invalid, and will display an 'Invalid Choice' message, and then go back to the main menu.... The main program does work properly, it's the 'Invalid' setup that is giving me problems
Code:
#include <iostream> #include <iomanip> using namespace std;
I wanna know why the program doesnt show "Invalid Letter Entered" when i enter any letter other than A S D or M
//Processing the data if (letter== 'A'||'S'||'M'||'D')// checking Add, subtract, multiply or divide { if (letter== 'A')//Adding the integers cout<<"Adding two integers = "<<first + second<<endl; else if (letter== 'S')//Subtracting the integers {
I made a program and when I try to use the main driver to instantiate everything it says invalid storage class for a function. All of my code is in 4 separate files i'm just trying to get it to run now.
I am getting this error invalid use of non static data member.my code looks something like this: i have a main.cpp and 2 class files with respective .h files, say one class file is named human (so i have human.cpp and human.h) and stats (so i have stats.cpp and stats.h) in my stats.h file, i have a double array: double HumanF[10][12] with everything filled in.then in my human.h file i just have a bunch of integers. human.cpp has formulas in it that use numbers from the double array i mentioned. for example
Human::Human() { constant (this is a double i made in human.h) = (1+Stats::HumanF[0][0]); i (another double) = pow(constant, ylvl); (ylvl is also an int I made in my header file) yhp = i*137; }