Question

The purpose of this question is to practice the pthread built in functions.

The following c program is a simple program to make a matrix of integers and print it.

//File name: a.c

#include <stdio.h>

#include <time.h>

#include <stdlib.h>

int** a;

int main(){

time_t t;

int m, n, i, j;       //m is the numbers of rows and n is the number of columns.

printf("Enter the number of rows, and columns: ");

scanf("%d%d", &m, &n);

printf("%d, %d\n", m, n);

srand((unsigned) time(&t));

a=(int**) malloc(m*sizeof(int*));

for(j = 0; j < n; j++)

    a[j] = (int*) malloc(n * sizeof(int*));

for(i = 0; i < m; i++)

    for(j = 0; j < n; j++)

      a[i][j] = rand() % 1000;

for(i = 0; i < m; i++){

    for(j = 0; j < n; j++)

      printf("%d,", a[i][j]);

    printf("\n");

}

return 0;

}

Your project uses pthread built-in functions based on the following conditions:

1. The program reads from the console the number of rows and the number of columns (like the above program). Therefore, the matrix has m rows and n columns.

2. The program creates m threads.

3. Each thread assigns random numbers to one row of the matrix.

4. The function main, sorts each row.

5. Each thread displays its sorted row.

6. The function: main displays the entire matrix.

Answer: ?

Answer 1

#include<stdio.h>

#include<pthread.h>

#include<unistd.h>

#include<stdlib.h>

#define MAX 4

void *mult(void* arg)

{

    int *data = (int *)arg;

    int k = 0, i = 0;

    int x = data[0];

    for (i = 1; i <= x; i++)

{

k += data[i]*data[i+x];

      }

    int *p = (int*)malloc(sizeof(int));

    *p = k;

    pthread_exit(p);

}

int main()

{

    int matA[MAX][MAX];

    int matB[MAX][MAX];

    int r1=MAX,c1=MAX,r2=MAX,c2=MAX,i,j,k;

printf("Enter the number of rows, and columns: ");

scanf("%d%d", &m, &n);

printf("%d, %d\n", m, n);

    for (i = 0; i < r1; i++)

            for (j = 0; j < c1; j++)

                   matA[i][j] = rand() % 10;

    for (i = 0; i < r1; i++)

            for (j = 0; j < c1; j++)

                   matB[i][j] = rand() % 10;

    for (i = 0; i < r1; i++){

        for(j = 0; j < c1; j++)

            printf("%d ",matA[i][j]);

        printf("\n");

    }

    for (i = 0; i < r2; i++){

        for(j = 0; j < c2; j++)

            printf("%d ",matB[i][j]);

        printf("\n");    

    }

    int max = r1*c2;

    pthread_t *threads;

    threads = (pthread_t*)malloc(max*sizeof(pthread_t));

    int count = 0;

    int* data = NULL;

    for (i = 0; i < r1; i++)

        for (j = 0; j < c2; j++)

               {

            data = (int *)malloc((20)*sizeof(int));

            data[0] = c1;

            for (k = 0; k < c1; k++)

                data[k+1] = matA[i][k];

            for (k = 0; k < r2; k++)

                data[k+c1+1] = matB[k][j];

                pthread_create(&threads[count++], NULL,

                               mult, (void*)(data));

}

printf ("After arranging rows in ascending order\n");

   for (i=0;i<m;++i) {

         for (j=0;j<n;++j) {

                  for (k=(j+1);k<n;++k) {

                        if (matA[i][j] > matA[i][k]) {

                           a = matA[i][j];

                           matA[i][j] = matA[i][k];

                              matA[i][k] = a;

                        }

                  }

            }

      }

      for (i=0;i<m;++i) {

            for (j=0;j<n;++j) {

                  printf (" %d",matT[i][j]);

            }

            printf ("\n");

      }

      printf ("After arranging the columns in descending order \n");

      for (j=0;j<n;++j) {

            for (i=0;i<m;++i) {

                  for (k=i+1;k<m;++k) {

                        if (matB[i][j] < matB[k][j]) {

                              a = matB[i][j];

                              matB[i][j] = matB[k][j];

                              matB[k][j] = a;

                        }

                  }

            }

      }

      for (i=0;i<m;++i) {

            for (j=0;j<n;++j) {

                  printf (" %d",matB[i][j]);

            }

            printf ("\n");

      }

}

    printf("RESULTANT MATRIX IS :- \n");

    for (i = 0; i < max; i++)

    {

      void *k;  

      pthread_join(threads[i], &k);

      int *p = (int *)k;

      printf("%d ",*p);

      if ((i + 1) % c2 == 0)

          printf("\n");

    }

  return 0;

}

}