Does rand() indeed produce a random value when the random number generator has been seeded?

I know that in order to avoid repeating the same output of the rand() function a pseudo-random number generator must be seeded with the srand function. That means, if I try say srand(1), the output of the rand() will be one value, if I try srand(2), the output will contain another value. But when I try the first argument again like srand(1), the value will be the same as in the first output. This issue made me think that all random values would be predictable in some way. Is it possible to have different output for the same seed (say if I try the same seed tomorrow)? Or are random values predictable indeed?