matrix multiplication using shared memory and fork - c++

Question

i have assigment to create c++ program which will multiple 2 uknown size matrix using fork and shared memory, I have write this code but at the end for multiplication result i get all zeros. Sorry for mess code im new in this.
`
`#include<iostream>
#include<math.h>
#include<vector>
#include<signal.h>
#include<unistd.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include<sys/wait.h>
using namespace std;
int l, m, n, job_numb;
key_t id_shared_mem;
int **B, **C, **A;
int **generateMatrix(int **matrix, int iterator, int vel){
for (int i = 0; i < iterator; i++)
{
matrix[i] = new int[vel];
for (int j = 0; j < vel; j++)
{
matrix[i][j] = (rand() % 9);
}
}
return matrix;
}
int **generateMatrixC(int **matrix, int iterator, int vel)
{
for (int i = 0; i < iterator; i++)
{
matrix[i] = new int[vel];
}
return matrix;
}
void *writeMatrixResult(int **matrix, int stupac, int red)
{
for (int i = 0; i < stupac; i++)
{
for (int j = 0; j < red; j++)
{
cout << matrix[i][j] << " ";
}
cout << endl;
}
return NULL;
}
void write()
{
cout << "Mnozenik = " << endl;
writeMatrixResult(A, l, m);
cout << "Mnozitelj = " << endl;
writeMatrixResult(B, m, l);
cout << "Umnozak = " << endl;
writeMatrixResult(C, l, l);
}
void abort(int sig) {
if (sig == SIGINT) {
for (int i = 0; i < job_numb; i++) wait(NULL);
shmdt(A);
shmdt(B);
shmctl(id_shared_mem, IPC_RMID, NULL);
} else {
write();
shmdt(A);
shmdt(B);
shmctl(id_shared_mem, IPC_RMID, NULL);
}
exit(0);
}
void proces(int procesId)
{
while (job_numb > procesId)
{
int i = 0;
while (i < l)
{
int j = 0;
C[procesId][i] = 0;
while (m > j)
{
C[procesId][i] = C[procesId][i] + A[procesId][j] * B[j][i];
j++;
}
i++;
}
procesId++;
}
}
int main(int argc, char ** argv) {
if (argc != 4) {
cout << " unesite 3 argumenta!" << endl;
return 0;
}
l = atoi(argv[1]);
m = atoi(argv[2]);
n = atoi(argv[3]);
job_numb = l / n;
if (l % n) {
job_numb++;
}
id_shared_mem = shmget(IPC_PRIVATE, sizeof(int) * 10, 0600);
sigset(SIGINT, abort);
A = (int **)shmat(id_shared_mem, NULL, 0);
B = A + l;
C = B + l * m*m;
A = new int *[l];
B = new int *[m];
C = new int *[l];
srand(time(NULL));
A = generateMatrix(A,l, m );
B = generateMatrix(B,m,l);
C = generateMatrixC(C,l,l);
for (int i = 0; i < n; i++)
{
switch (fork()) {
case 0: { //dijete
proces(i);
exit(0);
}
case -1: { //greska
cout << "Fatalna pogreska!" << endl;
exit(1);
}
}
}
for (int i = 0; i < job_numb; i++) wait(NULL);
abort(0);
}`
`
i have try to assign only one value to matrix C like c[1][1] = 2 in proces function to see if it will write any, but still im getting all zeros on printl.