Hello. I am currently working on a school project. I need to implement 4x4 matrix multiplication with multi-threads (pthread) doing each multiplication. By studying the assignment description and other codes found online, I was able to get a general idea of what I need to do. However, I am having trouble figuring out how to obtain input for the matrices. I am used to using a for loop with cin function to get each row, column input.

for (row=0; row<height; row++) {
        	for (column=0;column<width;column++) {

However, the professor requires me to use

void matrix_input(int mat[][dim], char* name)

implementation to get input. I am stumped. Also because I cannot figure out how to get input, I am having trouble implementing the calculation and print functions too. Please provide help as to how I can implement the input function. Here is what I have come up with so far. Thank you!

#include <pthread.h>
#include <iostream>
#include <iomanip>
using namespace std;

struct v {
	int i; // row
	int j; // column

const int dim = 4;
int A[dim][dim];
int B[dim][dim];
int C[dim][dim];

//void *calc_mat( void *param );	// the thread
//void matrix_input( int mat[][dim], char* name);
//void matrix_print( int mat[][dim] );

v matrix;

int main() {

	// get input for matrix A and B
//	matrix_input( mat[][dim], A);
//	matrix_input( mat[][dim], B);

	// thread indentifier
	pthread_t tid[dim][dim];

	// set of thread attributes
	pthread_attr_t attr;

	// get the dedault attributes
	pthread_attr_init( &attr );

	// create threads
	for( i=0 ; i < dim ; i++ ) {
		for( j=0 ; j < dim ; j++ ) {
			struct v *data = (struct v *) 
					malloc(sizeof(struct v));
			data->i = i;
			data->j = j;

			pthread_create( &tid[i][j], NULL, calc, &data);

	// wait for the threads to end
	for( int c=0 ; c < dim ; c++ )
		pthread_join( tid[c], NULL );

	// print out the matrix


	return 0;



void matrix_input( int mat[][dim], char* name ) {



void matrix_print( int mat[][dim] ) {



void* calc_mat( void* param ) {
//multiply A[i][j] * B[i][j] and store in C[i][j]

	pthread_exit( 0 );


How do I delete this thread?
I made a double post by mistake.

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