public void Q1_7()
        {
            int[,] matrix = new int[, ] {
                { 1, 2, 3 }, { 4, 0, 6 }, { 7, 8, 9 }
            };
            DataStruct.Q07_SetZeros(matrix);

            int[,] expectedAnswer = new int[, ] {
                { 1, 0, 3 }, { 0, 0, 0 }, { 7, 0, 9 }
            };
            Assert.IsTrue(matrix.Cast <int>().SequenceEqual(expectedAnswer.Cast <int>()));
        }