c – Do you need to add the `u` suffix to unsigned integers?

I know the you suffix means & # 39; unsigned & # 39; But is in necessary in the following code?

uint32_t hash = 2166136261u;

Is it a question or a convention? Or does it have a technical meaning in this case? The value must be converted to unsigned anyway because uint32_t is unsigned.

When should I and when should not I use you suffix for unsigned integer values?