код Вадима

program matrix;
{$APPTYPE CONSOLE}
uses
    SysUtils ;
type
    dynamic_array = array of array of integer ;
var
    matrix_first, matrix_second: dynamic_array;
    flag: string;
    correctreading : boolean ;

    procedure read_file(addres: String; var array_tmp : dynamic_array );
    var
        matrix_file : Text;
        i , j : integer;
        correctvalue : boolean ;
    begin
        assign(matrix_file, addres);
        Reset(matrix_file);
        i := -1;
        correctvalue := true ;
        correctreading := true ;
        {$I-}
        while ((not Eof(matrix_file)) and (correctvalue)) do
        begin
            Inc(i);
            SetLength(array_tmp, i + 1);
            j:= -1;
            while not Eoln(matrix_file) do
            begin
                Inc(j);
                SetLength(array_tmp[i], j + 1);
                Read(matrix_file,array_tmp[i, j]) ;
                if IOResult <> 0 then
                begin
                    writeln('Check the data in the file.');
                    correctvalue := false ;
                    correctreading := false;
                end;
            end;
            Readln(matrix_file);
        end;
        CloseFile(matrix_file);
    end;

    procedure counting (var arr_a, arr_b : dynamic_array; flag : string );
    var
        index_i, index_j: integer;
    begin
        if flag = 'sum'  then
        begin
            for index_i := 0 to length(arr_a) - 1  do
            begin
                for index_j :=0 to length(arr_a[0]) - 1 do
                    arr_a[index_i][index_j] := arr_a[index_i][index_j] + arr_b[index_i][index_j];
            end;
        end
        else
        begin
            for index_i := 0 to length(arr_a) - 1  do
            begin
                for index_j :=0 to length(arr_a[0]) - 1 do
                    arr_a[index_i][index_j] := arr_a[index_i][index_j] - arr_b[index_i][index_j];
            end;
        end;
    end;
    // procedure for writing into file and console
    procedure writing_result( array_tmp : dynamic_array );
    var
        i , j : integer;
        matrix_result : text ;
    begin
        writeln('Calculation has been made successfully');
        assign(matrix_result, 'matrix_result.txt ');
        Rewrite (matrix_result) ;
        for i := 0 to length(array_tmp) - 1  do
        begin
            for j := 0 to length(array_tmp[i]) - 1  do
            begin
                write(matrix_result, array_tmp[i][j] , ' ');
                write( array_tmp[i][j] , ' ');
            end;
            writeln('');
            writeln(matrix_result,'');
        end;
        Close (matrix_result);
    end;
begin
    read_file('matrix_first.txt' , matrix_first);
    read_file('matrix_second.txt' , matrix_second);
    if correctreading then
    begin
        repeat
            write('Enter "sum" for the sum and "res" for residual: ');
            readln(flag);
            if ( (flag <> 'sum') and (flag <> 'res' ) ) then
                writeln('Invalid input. Try again.');
        until ((flag = 'sum') or (flag = 'res' ));

        counting(matrix_first , matrix_second , flag);
        writing_result( matrix_first );
    end;
    readln ;
end.