C++ ::  threads To Take Sequential Turns

Jun 30, 2014

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

int turn = 1;
int counter = 0;
int t, n;

[Code] ....

I found this program in a forum and it creates 1 to t threads with each thread pointing to the next and the last thread pointing to the first thread and it allows each thread to sequentially take a turn until all threads have taken n turns. That is when the program ends.

My doubt is if we see in void *tFunc(void *arg) function, first thread locks the mutex and then wait there forever till it's turn comes.Lets say if I spwan 1000 threads and they have take 10 turns each sequentially and what if a 550th thread locks the mutex as soon as the program starts and waiting for its turn which will never happen because still (turn=1) which means it's first thread's turn and first 549 threads have to complete their 1st turn before this 550 threda's turn comes.Doesnt this result in deadlock?

View 2 Replies


ADVERTISEMENT

C :: Program Where A Computer And Player Take Turns Rolling Dice

Feb 19, 2013

I am making a program where a computer and player take turns rolling dice.

There seems to be an issue somewhere in my loop where when the player selects from the possible dice choices, it rolls for the computer and does not select the choice and it immediately becomes the player's turn again.

I am trying to get it to where when the computer rolls the dice, it should display the list of possible values, and ask the user to hit the enter key in order for the computer to choose which value to select using the following command:

Code:
while ( getchar() != '
' ) ; I've tried it a hundred times and no matter where I put the command it still skips the computer's turn.

Below is my code:

Code:
while (compscore < 99 && playerscore < 99){
printf("You have rolled the following pair of dice:
");
a =("%i ", rand() % (MAX_VAL - MIN_VAL + 1) + MIN_VAL);
b =("%i ", rand() % (MAX_VAL - MIN_VAL + 1) + MIN_VAL);
multiply = a * b;

[Code] ....

View 11 Replies View Related

C++ :: Implement Source Code That Turns Numbers Into English Text

Apr 18, 2013

I have been working on the same problem as mp252 from an earlier thread and 4 days later, I appear to have it working. Mine only goes from 0-9999 though as I must move on!

Code:
#include <iostream>
#include <string>
int getThousands(int number);
int getHundreds(int number);
int getTens(int number);
int getUnits(int number);
void printNumber(int number);

[Code]......

I had a scrap of paper like a mad scientist trying to find relationships between numbers and the values that they would return through my functions. This is how I arrived at the conditions of my if statements in 'void printNumber'.

I have seen other code that allows a greater range but I can't quite follow it (yet):

C++ code by fun2code - 67 lines - codepad

View 1 Replies View Related

C++ :: Update Records Using Sequential Files?

Nov 3, 2013

How do i go about updating a specific record in sequential File using a primary key in c++. I used Inventory number as my primary key..

Code: int locate[2];
string fname, lname, add, name, address;
int num, foundit;
Customer customer;

[Code].....

View 6 Replies View Related

C/C++ :: Saving Sequential Files To Computer?

Feb 2, 2015

[size="5"][size="4"]

I am programming in C and am having some trouble finding the .txt file I saved after having run my program. It is likely a stupid error on my behalf. However, it is causing me quite a bit of grief at the moment. I attached my source code below  
abgcchp27ex1.txt (2.01K)

I coded my structure within my header file(bookInfo.h) correct along with everything else. My dilemma is a matter of my file location and whether it actually saved.

/* This program takes the book info program from chapter 27 and writes the info to a file named bookinfo.txt. */

// First include the file with the structure definition

#include "bookInfo.h"
#include
#include
FILE * fptr;

[Code]....

View 3 Replies View Related

C++ :: Sequential Reading Blocks Of Lines From A File

Aug 14, 2014

I have a file that I need to read in blocks. I need to read in n lines at a time, do some processing, and then read in the next block of n lines until the file is done. I know the size of the block, but not the number of lines in the file unless I check that first. Normally I would read in like,

Code:
// declarations
string new_input_line, input_file;
// create an input stream and open the input_file
ifstream input_file_istream;
input_file_istream.open( input_file.c_str() );

[Code] .....

// process through data_block

With this approach, I'm not sure how I would keep looping to read the next block until I hit the end of the file without knowing how many lines are in the input file. I could process the file to find that out, or get that number from bash and pass it it as an argument, but it seems like that shouldn't be necessary.

I could also read in and store the entire file as a vector of string and then process through it afterwords, but that would not be a very efficient use of memory.

View 1 Replies View Related

C/C++ :: Sequential Matrix Multiplication - Error In Execution Time

Apr 30, 2014

I wrote program for Sequential matrix multiplication .But after execution for any input value( ex. 100,150,400) it shows the execution time is 0.000 msec.

#include <stdio.h>
#include <math.h>
#include <sys/time.h>
void print_results(char *prompt, int N, float *a);
int main(int argc, char *argv[])

[Code] ......

View 2 Replies View Related

C/C++ :: Sequential Matrix Multiplication Program - Syntax Error Near Unexpected Token

Apr 30, 2014

I wrote a sequential matrix multiplication program in c.

After execution i get error like
./mul.c: line 11: syntax error near unexpected token `('
./mul.c: line 11: `int main(){'

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define wA (30 * 16)
#define wB (50 * 16)
#define hA (80 * 16)
#define hB wA
#define wC wB

[Code] ....

View 4 Replies View Related

C++ :: Simulated Radio Station Holding A Contest - Guess Number / Sequential Search

Dec 14, 2014

I have an assignment to write the code for a simulated radio station holding a contest. The contest is for a "caller" (user input obviously) to guess a number from 1 to 500. The "randomly generated" numbers are already chosen and are being stored in a .txt file. The code is to search for number guessed by the caller and if they are wrong, next caller until a caller is correct. The end result is to display the winning number, the indexed location the number was found, and how many callers guessed. This is what I have...

Code:
#include<iostream>
#include<fstream>
using namespace std;
int sequenSrch(const int prizeArray[], int arrayLength, int searchedItem);
int guess();

[Code] ....

I'm not sure if I am even on the right track... when I pass something into the sequenSrh(); the code compiles, asks for the number to be guessed and ends.

View 2 Replies View Related

C :: Use SIGNALS To Control Threads

Nov 11, 2013

I've to use SIGNALS to control threads. Here's my code without the use of signals as I'm no good at that

Code:

#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
}

[code]....

View 4 Replies View Related

C++ :: Encapsulate Two Threads In A Class?

Apr 29, 2014

how to encapsulate two threads in a class?

View 1 Replies View Related

C++ :: Stopping Threads Without Using Local Var?

Aug 31, 2014

Here's my code,

#include <iostream>
#include <unistd.h>
#include <thread>
using namespace std;
void Blink();

[Code] .....

The problem is i don't want to use local vars , is ther anyway do end the loop safely(removing all the vars used in function and etc) without using a local var ?

View 3 Replies View Related

C/C++ :: Suspending And Resuming Threads

Apr 18, 2014

#include <stdio.h>
#include <pthread.h>
int i; // loop control variable
int *id; // array used to pass parameter of id
int nThreads; // #threads

[Code]....

I want to know where I am going wrong. I am strong in java but not in c so that may be my problem.

View 9 Replies View Related

C++ :: Creating And Terminating Threads?

Aug 31, 2014

I had a requirement where i needed to create a thread and if the execution of thread is not completed in 5 minutes i needed to terminate its execution and continue with other part of the code.

I used the below code to create the thread

_beginthread(FuncnCall,0,NULL);

HANDLE hThread = GetCurrentThread();

Then after this code, I used the below code to check for 5 minutes

for (int i=1;i<=0;i++) {
printf("Value of i=%d
",i);
if(threadFinished) {
break;
} else {
Sleep(1000);
}
}

After this if the value of "threadFinished" is false then i am terminating the thread like below

if(threadFinished == false) {
TerminateThread(hThread,0);
CloseHandle(hThread);
}

The Problem here is, after terminating the thread, the program abruptly closes by giving fatal error. Looks like memory leakage is happening after terminating the thread. Is it not the right way to safely exit the thread?

View 2 Replies View Related

C++ :: OpenMP - Intervals Assigned To Threads?

Feb 6, 2014

Is there a way of knowing which indices a thread is assigned in a parallel openMP scope?

View 6 Replies View Related

C :: Double Linked Structure Between 2 Threads

Jun 2, 2014

I am on a little project involving TCP socket-programming and multiple threads but need passing structures between two threads.

The first thread receives data with respective ID, temp, etc,.. Each ID is a list-item of a linked list and every ID has again a linked list of all the received data.

The second thread just have to access the list and perform some manipulations on it.

My solution: pass the head pointer of the linked list. Easy enough, right? Somehow, I am stuck receiving error message:" dereferencing pointer to incomplete type."

For the sake of ease and simplicity I just added a stripped down version of the project.

The magic (or not) happens in MainProcess.c: The Data thread should receive the pointer (a think) from the Connection thread.

View 5 Replies View Related

C++ :: Profiling Code - 4 Threads Slower Than 1

May 9, 2013

I am doing something wrong since for me 4 threads perform 2 times slower then 1.I have 2 vectors with bunch of data to process, there is no concurrency (not moving elements and are independent of each other) so i just need to calculate some data from one and copy result in another.

LARGE_INTEGER getFrequency()
{
LARGE_INTEGER frequency;
QueryPerformanceFrequency(&frequency);
return frequency;

[code].....

View 7 Replies View Related

C++ :: Create Two Threads Calling Even And Odd Functions

Mar 1, 2013

I want to create two threads which will be calling even and odd functions where even function should print even number and odd function should print odd number.Can it be possible with condition variable? What is the code in both the cases i.e. two separate function and with condition variable.

View 6 Replies View Related

C Sharp :: Stopping And Resuming Threads?

Jul 9, 2012

how do I stop and restart a Thread in C# once it reaches a certain location on a form then restart the thread once it goes outside of the location boundries?

I am trying to stop an animation thread (a bullet) once it reaches a block on a panel.

View 1 Replies View Related

C++ :: Threads Never Execute In Arbitrary Order?

Jul 25, 2014

Code:

void Arrival_MainThread::Body () {
t1 = new boost::thread((Arrive_Fctor()), 2);
t2 = new boost::thread((Arrive_Fctor()), 10000);
t3 = new boost::thread((Arrive_Fctor()), 3000);

Code:
class Arrive_Fctor {
public:
void operator()(int mean) {
m_Arrivals = new Arrivals(mean);
m_Arrivals->Activate();
#ifndef NO_RESOURCE

[code].....

The order of arrivals always appear as 3,2,1 it can't be 1,2,3 or 3,1,2 or something like that?

The body method is called when m_Arrival->Activate() is executed, and it is running as an independent thread.

View 4 Replies View Related

Visual C++ :: Can Two Functions In Same DLL Be Called By Two Threads?

Aug 27, 2014

I write a DLL MyDLL.dll with Visual C++ 2008, as follows:

(1)MFC static linked
(2)Using multi-thread runtime library.

In the DLL, this is a global data m_Data shared by two export functions, as follows:

ULONGLONG WINAPI MyFun1(LPVOID *lpCallbackFun1) {
...
Write m_Data(using Critical section to protect)

[Code]....

Although MyThread1 and MyThread2 using critical section to protect the shared data m_Data, I will still suspend MyThread1 before accessing the shared data, to prevent any possible conflicts.

The problem is:

(1)When the first invoke of MyFun2, everything is OK, and the return value of MyFun2(that is nResult2) is 1 , which is expected.

(2)When the second, third and fourth invoke of MyFun2, the operations in MyFun2 are executed successfully, but the return value of MyFun2(that is nResult2) is a random value instead of the expected value 1. I try to using Debug to trace into MyFun2, and confirm that the last return statement is just return a value of 1, but the invoker will receive a random value instead of 1 when inspecting nResult2.

(3)After the fourth invoke of MyFun2 and return back to the next statement follow MyFun2, I will always get a "buffer overrun detected" error, whatever the next statement is.

I think this looks like a stack corruption, so try to make some tests:

1.I confirm the /GS (Stack security check) feature in the compiler is ON.

2.If MyFun2 is invoked after MyFun1 in MyThread1 is completed, then everything will be OK.

3.In debug mode, the codeline in MyFun2 that reads the shared data m_Data will not cause any errors or exceptions. Neither will the codeline in MyFun1 that writes the shared Data.

View 4 Replies View Related

C++ :: Accessing And Working With Vector From Multiple Threads

Oct 20, 2014

I have a vector that I would like to access and work with from multiple threads. I have created an example below to illustrate the functionality that I would like to accomplish.

The goals are to be (1) high speed, (2) thread safe, and (3) *if possible* continue to use vectors as my larger project uses vectors all over the place and as such I would like to maintain that.

However, if I need to switch from vectors to something else then I am open to that as well.

The following example below compiles but crashes rather quickly because it is not thread safe.

How I can fix the example below which I can then apply to my larger project?

#include <string>
#include <vector>
#include <ctime>
#include <thread>
#include <iostream>
#include <random>
#include <atomic>
#include <algorithm>
enum EmployeeType {

[Code] ....

View 1 Replies View Related

C++ :: Solving Linear System Of Equations Using Threads

Dec 14, 2014

I am trying to write a code that solves a system of linear equations such as A*B=C. My system has a dimension equal to 1600. The matrix A cab be separated into 4 sub matrices and each can be handled by a different thread. I tried to solve this using the following code:

int main() {
int count = 0;
//Inputing matrix A
ifstream matrix;
matrix.open("example.txt");

[Code] ....

Although the above code gives the correct answer, the time needs to find the solution is bigger than that needed without using threads.

View 1 Replies View Related

C++ :: Reading / Writing File On Multiple Threads?

Aug 7, 2013

I'm currently working on a server for handling clients in a 2d online game and I wrote some regular fstream file code for handling the file that stores their information and I was about to implement it into the server, then I realized there might be a problem having it open multiple times concurrently, so I googled it and came up with
posts like

[URL]

I'm wondering if I can just treat it like everything else or will I have to do something specific for opening on multiple threads?

p.s. I did read those posts but I'm very new to multithreading

View 16 Replies View Related

C++ :: Passing Data Between Threads Without Using Global Variables

Nov 6, 2013

I have a main thread and a worker thread. How do i pass data between them when both are already running without using global variables?

View 1 Replies View Related

C :: Consumer And Producer Threads Aren't Synchronizing Correctly?

Dec 3, 2013

I have a school assignment to create a program that uses a producer thread to create a series of random numbers, and a consumer thread to read those numbers (via a shared bounded buffer), and record the min, max, average, and number of items. Now, the threads aren't synching well. Here's my code:

Code:
#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>

pthread_cond_t empty;
pthread_cond_t full;
int done = 0;
pthread_mutex_t lock;

[code] ....

And output:

Code:
Producer in for
Consumer Entering While
Consumer reading item 0
Producer making item 0
Consumer reading item 1
Consumer reading item 2
Consumer reading item 3
Producer making item 1
Producer making item 2
Producer making item 3
Producer making item 4
Producer making item 5
Producer making item 6
Consumer reading item 4
Minimum: 0
Maximum: 4978
Average: 995
Items Produced: 5

View 4 Replies View Related







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