Use Fork() to create Child process that use separate threads

[Jmac21]

Hey guys, How can I create a fork()/Child thread process for each computation in my program: Average, median, and standard deviation of the grade population, display the sorted the grades, and display a graph of the statistics all while using the prototype: void* nameOfFunction(void* param) for each function called to execute the thread and the Pthread create_thread system call to create each required thread.

#include <iostream>

#include <iomanip>

#include <cmath>

using namespace std;

// function declarations

double getAverage(int* grades, int size);

double getMedian(int* grades, int size);

double getSd(int* grades, int size);

void sortGrades(int* grades, int size);

int main()

{

// Declaring variables

int size, val;

// setting the precision to two decimal places

std::cout << std::setprecision(2) << std::fixed;

// Getting the input entered by the user

cout << "How many Number of Grades For Child Process?? :";

cin >> size;

// Creating array dynamically

int* grades = new int[size];

/* Getting the inputs entered by the user

* and populate those values into array

*/

for (int i = 0; i < size;)

{

while (true)

{

cout << "Enter the grade for each #" << i + 1 << ":";

cin >> val;

if (val < 0 || val>100)

{

cout << "** Invalid.Must be between 0-100. **" << endl;

continue;

}

else

{

grades[i] = val;

i++;

break;

}

}

}

// calling the functions

double avg = getAverage(grades, size);

double median = getMedian(grades, size);

double sd = getSd(grades, size);

sortGrades(grades,size);

  

//displaying the average , median ,Standard Deviation
cout<<"Child process has completed the average computation"<<endl;
cout <<"Child process can now display the Average! :"<<avg<<endl;

cout<<"Child process has completed the median computation"<<endl;
cout <<"Child process can now display the Median!:" << median << endl;

cout<<"Child process has completed the Standard-deviation computation"<<endl;
cout << "Child process can now display the Standard Deviation :" << sd << endl;

  

//Displaying the array elements after sorting

cout<<"Child process will now display the sorted Grades After Sorting the Grades :"<<endl;

for(int i=0;i<size;i++)

{

cout<<grades[i]<<" ";

}

cout<<endl;

//Displaying the graph
cout<<"Child process will now Graph"<<endl;
cout<<"\nGraph is displayed below:"<<endl;

for(int n=0;n<100;n+=20)

{

cout<<n<<"-"<<n+20<<"\t";

for(int m=0;m<size;m++)

{

if(grades[m]>=n && grades[m]<n+20)

cout<<"*";

}

cout<<endl;

}
cout<<"Child process has completed graphing"<<endl;
cout<<"Child process has completed all task"<<endl; 



return 0;

}

// This function calculates the average of grades

double getAverage(int* grades, int size)

{

double sum = 0.0;

// calculating the sum of res[] array elements

for (int i = 0; i < size; i++)

{

// calculating the sum

sum += grades[i];

}

// calculating the average

double avg = sum / size;

return avg;

}

// This function calculates the median of grades

double getMedian(int* grades, int size)

{

// This Logic will Sort the Array of elements in Ascending order

int temp;

int middle;

double median;

for (int i = 0; i < size; i++)

{

for (int j = i + 1; j < size; j++)

{

if (grades[i] > grades[j])

{

temp = grades[i];

grades[i] = grades[j];

grades[j] = temp;

}

}

}

if (size % 2 == 0)

{

middle = size / 2;

median = (float)(grades[middle - 1] + grades[middle]) / 2.0;

}

else

{

middle = (size + 1) / 2;

median = grades[middle];

}

return median;

}

// This function calculates the standard deviation of grades

double getSd(int* grades, int size)

{

int sum_of_squares = 0, standard_deviation;

double variance;

double avg = getAverage(grades, size);

/* This loop Calculating the sum of

* square of eeach element in the array

*/

for (int i = 0; i < size; i++)

{

/* Calculating the sum of square of

* each element in the array

*/

sum_of_squares += pow((grades[i] - avg), 2);

}

// calculating the variance of an array

variance = ((double)sum_of_squares / (size));

// calculating the standard deviation of an array

standard_deviation = sqrt(variance);

return standard_deviation;

}

void sortGrades(int* grades, int size)

{

//This Logic will Sort the Array of elements in Ascending order

int temp;

for (int i = 0; i < size; i++)

{

for (int j = i + 1; j < size; j++)

{

if (grades[i] > grades[j])

{

temp = grades[i];

grades[i] = grades[j];

grades[j] = temp;

}

}

}

}

[helios]

I don't quite understand your question. fork() creates a new process. Separate processes by definition execute separate threads, therefore fork(), in creating a new process, creates a new thread as well.
Which is it? Do you want to create a new process (with a new thread to go with it) or create a new thread within the same process?

[Jmac21]

the main function, the child process uses separate threads to compute the average, median, and standard deviation of the grade population, display the sorted the grades, and display a graph of the statistics. threads belonging to the same process can share global data