data function for vector and matrix

headers/vmath.hpp/vmath_mat.hpp

@@ -204,10 +204,18 @@ namespace vmath_hpp
         void swap(mat& other) noexcept(std::is_nothrow_swappable_v<T>) {
             for ( std::size_t i = 0; i < Size; ++i ) {
                 using std::swap;
-                swap((*this)[i], other[i]);
+                swap(rows[i], other.rows[i]);
             }
         }
 
+        [[nodiscard]] constexpr pointer data() noexcept {
+            return &rows[0];
+        }
+
+        [[nodiscard]] constexpr const_pointer data() const noexcept {
+            return &rows[0];
+        }
+
         [[nodiscard]] constexpr reference operator[](std::size_t index) noexcept {
             return rows[index];
         }