Is it difficult to get into graduate school for applied math with a computer science degree? I'm a computer science student in my third year of undergrad. I've been taking math classes on the side and will have finished most of the applied math major by the time I graduate.

I'm wondering how difficult it would be to get into graduate school for applied math with a computer science undergrad degree. I could possibly switch over to the applied math major if that would make graduate school admissions easier, but I'm wondering if it would also be fairly possible with a computer science undergrad.
There's no reason why you couldn't get into an applied math graduate program with a CS bachelor's degree.  Some parts of some applied mathematics programs are called computer science in other programs (and vice versa).  Many applied mathematics students come from engineering, physics, CS, and other undergraduate programs.