the compiler doesnt accept void functions used with threads (for the first time and all of sudden!?)
#include <cstdlib>
#include <thread>
#include <windows.h>
[Code]....
this is a sigment of my code. Compiler says that the error occurs in line 47 (marked by ***). Leaving out the braces makes it even worse.
I have designed a class called matrixType that has some overloaded operators (+, -, *, and <<); the arithmetic operator functions of which are overloaded as member functions of the class. As an alert mechanism, I want a message displayed when two matrices of dissimilar sizes are added/subtracted OR when two incompatible matrices are being multiplied. Displaying this error message is not the problem. However, I want a scheme where on detecting two matrices’ incompatibility, the operator function returns the error message (a string datatype) instead of what would be an erroneous result (the expected matrixType object).
In other words, what I may be essentially asking is: Is it possible for a function, say,
matrixType matrixType::operator+(const matrixType& otherMatrix) const
{
.
.
.
}
to return a dataType (like a string) other than the expected matrixType?
I have a class which I wrote and one of its object is "SerialPort" .NET class. In my MainWindow I created instance of my class called "SerialPortComm", then I send through some functions of mine, commands to the Serial Port, and I receive answers through "DataReceived" event.
But when I trying to use Dispatcher.BeginInvoke to write my data I have received (successfully), nothing shows on the RichTextBox which I'm trying to write to.
What can caused that, and How I can make it works?
SerialPortComm.cs
public partial class SerialPortComm : UserControl {
public SerialPort mySerialPort = new SerialPort();
public void Open_Port(string comNumber, int baudRate) {
mySerialPort.PortName = comNumber;
mySerialPort.BaudRate = baudRate;
[Code] ....
Here is the function I am trying to modify...
Code:
void DisplayAdminMenu() {
char ch;
system("cls");
printf("Admin Menu");
[Code] ......
Error! Must enter a number between 1 and 5
I am trying to cout just the first 5 characters the user enters into a string. I'm not sure how I can discard or not show the rest of the characters they try to enter after 5.
#include <iostream>
#include <string>
using namespace std;
int main() {
string random;
cout << "Enter any word." << endl;
cin >> random;
cout << random; //want to ignore everything after first 5 characters entered.
return 0;
}
In a rather large codebase, there is a set of recurring calls to a couple vararg functions (mainly for logging)
Code: logthis(foo, bar(), somefunction(parameter1,parameter2), somethingelse);
The number of parameters to this function is variable It has all types of variables, function calls, etc.
The code has thousands of these lines
There is now a need for a special version of the compile that will remove a lot of the code, among others is the logging.
Can I somehow #define the "logthis" name into something that'll remove all actual calls to the code. including the actual parameters/expressions to the call.
I can't afford to add #ifdef/#endif around each of the calls because there are too many of them, and because that'll cause some undisired side effects in our code conformance tests.
Code: #define logthis __noop
comes close, that removes the call, but it still causes the compiler to evaluate and validate all the parameters to the logthis function, which doesn't work because in this case, removing the logging headers also removes other members of the class that get used as part of the parameters to logthis()
if I could define logthis into // resulting in all the rest of the line being comments, but that doesn't work.
Preferably I'd like something to be portable, but I'll take a solution that only works on visual studio as well.
So i have this program that takes in user input and stores them into an array and then prints them, removes duplicates, and sorts in ascending order. The user can also stop by inputting a sentinel value (in this case -1). But i am also supposed to ignore any negative value besides -1. When i input any other negative value into the program it messes up. How would i go about ignoring the negative values?
Code:
#include<stdio.h>
int main()
{
int input, nums[20], i, j, k, temp, count=0, count2=0;
for(i=0;i<20;i++)
[Code] .....
I know I can use -isystem path to mark a path as containing system headers which shouldn't be included when generating warnings, and this works, but it doesn't work when the warnings are generated by instantiating templates from the library in my source code. Is there any way to ignore these template-instantiation-generated warnings too?
View 13 Replies View Relatedhow I can ignore strings from being entered by the user. When the use enter's a string it always evaluates it as even. I though I might use a cin.ignore(); but I am unaware of how to use it.
#include <iostream>
using namespace std;
int main() {
cout << "Enter a number: ";
int num = 0;
[Code] ....
I have made a new data type which named LongDouble
it takes 16 byte to save the number
the first bit for the sign
the next 15 bit for the exponent
the other 112 bit for the mantissa
I have to apply four operation on these numbers , but i have a problem in addition , when the sign for any of the numbers is negative ,how i can perform the operation , also if there is a Mantissa how i can also perform the operation?
if i try to save mantissa in a variable there would a loss of precision ... Here's my code
LongDouble LongDouble::operator+(const LongDouble& olong) {
LongDouble temp;
if (this->sign == 0 && olong.sign == 0) {
temp.exponent = this->exponent + olong.exponent;
[Code] .....
I want to write a c++ code, which will read in a file like this:
A: 10
B: 20
C: 30
while in the code, I would need the value of A B C, how can I let the cin ignore the labels like A:?
of course, I can write a file as
10
20
30
.
.
.
and use cin>>A>>B>>C; to read in those
but in this way, when the number of values increase, it is really hard to remember who is who?
The following Program ask a user to input a sentence. Program alphabetically sort individual character for each word.
My problem is, how do I ignore case sensitive if a user enters a uppercase letter. I try using stricmp but ran into some errors.
Below code:
#include <iostream>
#include <string>
#include <algorithm>
#include <string.h>
using namespace std;
void bubblesort(char a[]);
int main() {
char sent[50];
[Code] ....
Current output:
input: today is a great day
output: adoty is a aegrt ady
Using Uppercase:
input: Today is a Great Day
output: Tadoy is a Gaert Day
What I want:
input: Today is a Great Day
output: adoTy is a aeGrt aDy
I just wanted to know a way to cut off any remaining zeroes from a double data type. I' trying to calculate cost and output it but it keeps adding a bunch of zeroes on the end. I know there must be a way to
View 1 Replies View RelatedMy code:
#include<cstdio>
#include<iostream>
using namespace std;
main() {
long double j;
scanf("%Lf", &j);
cout<< j;
return 0;
}
If I give any number as input, the output is always 0. why? where's the problem ? p
I've written a simple program, which asks the user to respond to a YES or NO question using the character Y/y for YES and the character N/n for NO. The foundation of this program is based around several IF statements implemented to aid in finding the ASCII value of the character entered before invoking the corresponding cout statement that informs the user which character they entered. My Question: How should a program be written to deal with ignoring case sensitivity in regards to the users' input?
Here is my amateurish attempt,
Code:
#include <iostream>
using namespace std;
int main()
[Code] .....
The following are IF statements written for the program to determine whether the user answered YES or NO. The program then performs the cout statement that contains the corresponding character to the ASCII value found.
*/
if(user_input == 121 || user_input == 89)
{
if(user_input == 121)
{
cout << "
[code]......
coming from Java, my experience with the Classes in C++ is quite limited.
Thats why I am having trouble converting the following (simple!) Java-Program.
Most examples with linked lists I found on the web describe how to implement the LinkedList class itself. But my problem is different: I want to use such a Class (I have a LinkedList class available on my system which is presumably OK).
Code: package main;
import java.util.ArrayList;
public class Main {
public static void main(String[] args) {
BoxList<String> sl = new BoxList<String>(
new ArrayList<ABox<String>>());
sl.getList().add(
new BoxPair2<String>(new BoxPair2<String>(
[code].....
My Fraction.h class looks like :
class Fraction {
int num;
unsigned int den;
public:
Fraction(int = 1,int =1);
//Constants of Datatype
[Code] ....
The implementation Fraction.cpp is as follows :
#include "Fraction.h"
Fraction::Fraction(int n, int d):num(n),den(d){
cout << This is double param constructor <<endl;
}
And the application main.cpp is
int main(){
Fraction f1(3,9);
f1 = Fraction::sc_fUnity; // how to implement this ?
}
How can I write the Fraction.cpp for the constant static member ?
How you would overload an operator for Common Data-types like "char" and "int".
I often use bool arrays to create a multilevel-trigger-systems, when iterating over multiple containers or waiting for two events to occur at the same time.
For example:
I would define..
bool trigger[2] = {0, 0};
And when doing work via a loop, I use it like so:
while(trigger[0] != 1 && trigger[1] != 1)
You can probably see where I'm going with this. I want to be able to use my bool array with the "!" operator.
So if "trigger == 0" (as a whole), it returns false.
How can I achieve this?
Can you create custom operators? Say if I wanted to create "or-gates" or "xor-gates" etc.
How to use static in a class, function and variable.
View 1 Replies View RelatedI am need to compare 2 items from 2 separate drop down lists. These values are of int type. Say for example 2 drop down lists showing years. Now i need to find out these 2 years selected is greater or nearer to the current year.
I tried converting the values i receive from the drop down lists to int variables. But i am getting error then. I gave it like below.
int tmp = Convert.ToInt32(ddl_1.SelectedItem.Text);
this gives an error like this - Input string was not in correct format.
I need to know how to put an item from a drop down list to a variable of int data type.
I have a class that is a template, I have to declare it in my main but i want the user to choose what type of data they will use in the class, I cant just declare myclass my, i have to use myclass<int> my, how can I change so user can select the proper datatype to use in the class.
View 5 Replies View RelatedI have the codes for such a problem where, to create a program that counts how many times the second string appears on the first string. Yes it counts if you put 1 letter only, but if you put 2, it is an error. As an example. If the first string is Harry Partear, and the second string is ar, it must count as 3. Here's the code:
Code:
#include <iostream>
#include <conio.h>
using namespace std;
int main ()
[Code] ....
I have the following code below. I am getting a memory access violation when accessing cmd->query_string in the loop function. The loop() function is running in another thread. The cmd object appears to be destroyed after calling the send_command function. How do I create an object on the heap and access the query_string.
std::list<my_command_message_que*> my_command_que;
void loop(){
if(my_command_que.size() > 0){
my_command_message_que * cmd = my_command_que.front();
std::cout << cmd->query_string;
[Code] ....
I've been using threading for a while, that was no needing parameters. so I used for example the following line :
_beginthread(functionName, 0, (void*)10);
and it worked great...
but now I have a function that has an int parameter (int num), and I dont know how to transfer it using _beginthread...
I was working on a problem that was best solved with chaining threads together using a blocking thread-safe queue. Eg threads A and B pass data to each other using a queue ... a simple producer consumer design A -> B. This has two benefits: 1) being that there is a buffer between the two threads to cache for a slow consumer and 2) allows for better throughput when loads of data are high because the two can run in parallel. Most of the time the design works well under load. but I found when pushing data through the threads intermittently, i.e. once about 0.5 seconds it ran poorly, mostly from what seemed to be latency introduced during the OS waking up of the consumer thread B.
What i have come up with to solve this issue is what i call an .... Its a wrapper around a basic thread safe queue and adds one extra function called .... The idea here is that if you have a simple case (or perhaps a slightly more complicated case) of two threads in a prod cons design and you know the producer will create or received the data, process it, and then push onto the queue, why not give the consumer thread a heads up to let it know the data is about to arrive. In this case call .... In this way you can have the consumer thread in a polling state anticipating the arrival of data and avoid the time to schedule it back to a running state.
Anyway, i have some code below and I was looking to get some feedback. I have tested it somewhat and it does improve the responsiveness quite substantially.
I don't know if I've setup the thread correctly or not, but its behavoir isn't what I'd expect. I'm creating the thread within a BN_CLICKED message
typedef struct my_TNFO {
HANDLE h_event;
HANDLE h_thread;
DWORD thread_id;
BOOL running;
BOOL init;
BOOL canceled;
[Code] ....
progd->count was devised to stop the thread when the recursion ended by posting a message to the main window. When it reaches 1, the def procedure sends the WMU_DISC_DONE message to set the event
All that *appears* to work; however, if I cancel the recursion thread, the list view continues to populate for a bit and then deletels all but 1 item though I send the message LVM_DELETEALLITEMS.
If I move the (tmp->canceled == TRUE) test inside of the do-while, the app gets loopy.