Write a C or C program A6p2.c(pp) that accepts one command line argument which is an integer n between 2 and 4 inclusive. Genera
te 60 random integers between 1 and 49 inclusive and store them in a 5 by 12 two dimensional integer array (i.e.,int a[5][12];). Use pthread to create n threads to square all 60 array elements in place. You should divide this update task among the n threads as evenly as possible. Print the array both before and after the update separately as 5 by 12 matrices.
1 answer:
Answer:
The code is as given below. The output is attached as the attachments
Explanation:
#include <iostream>
#include <cstdlib>
#include <pthread.h>
using namespace std;
#define c 12 // defining number of columns
#define r 5 //defining number of rows
int chunk; //initializing variable chunk
int n=0; //defining variable n as 0
int arry[r][c] ; //initializing the array as 5x12
void Squared(void threadid) {
long td; //initializing the variable td
td = (long)threadid; //typecasting threader to long
int s = td * chunk; //defining variable s for the start
int e=s+chunk-1;//defining variable e for the end
for(int i=0; i<r; i++){ //initializing for loop for rows
for(int j=0;j<c;j++){ //initializing for loop for columns
int pos = i*c + j; //defining variable
if(pos>=s&&pos<=e)//condition to make sure the values in within the chunk range
{
arry[i][j]=arry[i][j]*arry[i][j]; //squaring the terms
}
}
}
pthread_exit(NULL);
}
int main () {
cin>>n; //taking number n from 2 to 4 inclusive from the user
pthread_t threads[n];
int rc; //initializing variable rc for threads
int i,j,k; //initializing variables i,j,k
//filling array with data
for(i=0;i<r;i++) //for loop for rows
{
for(j=0;j<c;j++) //for loop for columns
{
arry[i][j]=(rand() % 49) + 1; //Creating random integers
}
}
//Printing Random Array
for(i=0;i<r;i++)
{
cout<<"\n";
for(j=0;j<c;j++)
{
cout<<arry[i][j]<<"\t";
}
}
chunk = (60 + n - 1) / n; // divide by threads rounded up.
for( i = 0; i < n; i++ ) {
cout << "\n main() : creating thread, " << i << endl;
rc = pthread_create(&threads[i], NULL, Squared, (void *)i); //creating the threads
if (rc) {
cout << "Error:unable to create thread," << rc << endl;
exit(-1);
}
}
//Printing Result Array
for(i=0;i<r;i++)
{
cout<<"\n";
for(j=0;j<c;j++)
{
cout<<arry[i][j]<<"\t";
}
}
pthread_exit(NULL);
}
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