what is better, a 35 or 45 mm lense?

The first question that MUST be answered is: What do you want to do?
It's like asking what's better a Ford F-150 or a Ferrari 458? Well, the Ferrari of course, right? Sure the Ferrari is an amazing car, but not when you need to haul 1500 pounds of manure from your pig farm.
They both are best at certain things, so without knowing what you want to do with it, or if your looking to only have one lens, no one can really help you.

Better for what?

By the way, the word is lens. There is no E at the end.

Since you don't give enough information, this can't be answered.
The better lens is the one that suits your style of shooting and meets your expectations.

Some things that are needed to make this determination:
What is manufacturer/model of the camera body (sensor size) of the camera?
What sort of field of view do you need?
Who are the manufacturers of the lenses?
What is the quality of the glass?
What is the maximum aperture?
What is the quality of the lens build?
What is the quality of the optics (coatings, various aberrations)?
What is the maximum magnification and what magnification will suit you?

Which is better, a moving truck or a motorcycle?

Neither is "better"
They simply have different focal lengths so you have to chose which one suits which occasions.

35mm. If you use a cropped sensor, 35mm gives you about 50mm focal length, which is standard for portrait. ;p

Are you asking about a DX or FF lens? What is the intended use of said lens?

35