Compile and Execute FORTRAN-95 Online

PROGRAM matmult
implicit none
   integer, dimension (:,:), allocatable :: array1
   integer, dimension (:,:), allocatable :: array2
   integer, dimension (:,:), allocatable :: array3
   integer :: L, M, N, i, j, k, k2, asum
   character (len = 15) :: l2, m2, n2


	! Prompt for 3 integers (call them L, M, and N)
	! They represent the dimensions of the arrays
	! The first array will be dimension L x M, the second will be M x N
	! and the product array, L x N
	
	CALL GET_COMMAND_ARGUMENT(1, l2)
	CALL GET_COMMAND_ARGUMENT(2, m2)
	CALL GET_COMMAND_ARGUMENT(3, n2)
	
	read(l2,'(i4)') L
	read(m2,'(i4)') M
	read(n2,'(i4)') N
	
	allocate (array1(L, M))
	allocate (array2(M, N))
	allocate (array3(L, N))

	
	! Initialize the first array such that array(i,j) = 10i+j
	do i = 1, L
        do j = 1, M
        array1(i,j) = (10*i)+j
        end do
    end do

	
	! Initialize the second array such that array(i,j) = 20i+2j
	do i = 1, M
        do j = 1, N
        array2(i,j) = (20*i)+(2*j)
        end do
    end do
    

	! Multiply arrays
	! Matrix multiplication C = AB
	!        C(i,j) = the sum product of row i of A and column j of B     
	do i = 1, L
        do j = 1, N
        

        do k = 1, M
            asum = asum + (array1(i, k) * array2(k, j))
        end do
        
        array3(i,j) = asum
        write (*,*) asum
        
        end do
    end do

	
	! Print the array row-by-row to STDOUT (terminal)
	! To print elements of an array in a row, you can define a loop as part of the WRITE
	! Assuming that vec is a one-dimensional array of length 5 and j is a declared variable,
	! the following will print that vector as a row
	! 		WRITE(*,*) (vec(j), j=1, 5)
	! L x N
	do i = 1, N
        WRITE(*,*) (array3(j,i), j=1, L)
    end do

	
	! Deallocate arrays
	! If you allocate it, you need to deallocate it
	deallocate (array1)
	deallocate (array2)
	deallocate (array3)

	
END PROGRAM matmult