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2 Commits

Author SHA1 Message Date
04c37c5078 blep 2023-12-02 14:55:13 +01:00
71fad746b3 Fix threads 2023-12-02 14:34:06 +01:00
4 changed files with 107 additions and 5 deletions

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@ -26,3 +26,4 @@ add_subdirectory(third-party/fmt)
# Include CMakeLists files from subdirs for specific tasks
add_subdirectory(task1)
add_subdirectory(task3)

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@ -7,14 +7,24 @@
},
"configurePresets": [
{
"name": "task1@release",
"displayName": "Task1 Release build",
"description": "Builds the targets of task1 as release",
"name": "task@release",
"displayName": "Task Release build",
"description": "Builds the target as release",
"generator": "Ninja",
"binaryDir": "${sourceDir}/.out/task1-release",
"binaryDir": "${sourceDir}/.out/task-release",
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Release"
}
},
{
"name": "task@debug",
"displayName": "Task Debug build",
"description": "Builds the target as debug",
"generator": "Ninja",
"binaryDir": "${sourceDir}/.out/task-debug",
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Debug"
}
}
]
}

8
task3/CMakeLists.txt Normal file
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@ -0,0 +1,8 @@
find_package(Qt6 COMPONENTS Core REQUIRED)
add_executable(task3-chpt3ex12)
target_sources(task3-chpt3ex12 PRIVATE
main.cpp)
target_link_libraries(task3-chpt3ex12 PRIVATE
Qt6::Core)

83
task3/main.cpp Normal file
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@ -0,0 +1,83 @@
#include <iostream>
#include <QSemaphore>
#include <QThread>
#include <QCoreApplication>
/*
* Barlas Chpt 3 Ex 12:
Create three threads, each printing out the letters A, B, and C.
The printing must adhere to these rules:
The total number of Bs and Cs that have been output at any
point in the output string cannot exceed the total number
of As that have been output at that point.
After a C has been output, another C cannot be output until
one or more Bs have been output.
Use semaphores to solve the problem.
*/
class Printer {
private:
QSemaphore &lockBC_;
QSemaphore &lockC_;
QString name_;
public:
explicit Printer(QSemaphore &lockBC, QSemaphore &lockC, QString name) : lockBC_(lockBC), lockC_(lockC),
name_(name) {};
void printA() {
this->lockBC_.release(1);
std::cout << name_.toStdString() << " A\n";
}
void printB() {
if (this->lockBC_.tryAcquire(1, 10000)) {
if (this->lockC_.available() == 0) {
this->lockC_.release(1);
}
std::cout << name_.toStdString() << " B\n";
}
}
void printC() {
if (this->lockBC_.tryAcquire(1, 10000)) {
if (this->lockC_.tryAcquire(1, 10000)) {
std::cout << name_.toStdString() << " C\n";
} else {
this->lockBC_.release(1);
}
}
}
};
class Worker : public QThread {
private:
Printer printer_;
public:
Worker(QSemaphore &lockBC, QSemaphore &lockC, QString tname) : printer_(lockBC, lockC, tname) {};
protected:
void run() {
printer_.printA();
printer_.printB();
printer_.printC();
}
};
int main(int argc, char *argv[]) {
QCoreApplication app(argc, argv);
QSemaphore lockC(1);
QSemaphore lockBC(0);
int N = 3;
Worker *workers[N];
for (int i = 0; i < N; i++) {
workers[i] = new Worker(lockBC, lockC, QString("Thread %1").arg(i));
workers[i]->start();
}
return app.exec();
}