c program to check whether a number can be expressed as sum of two prime numbers

Question

test case 1
input
35
output
not
test case 2
input
34=3+31
34=5+29
34=11+23
34=17+17
34

Answer 1

True. But it is believed (although not yet mathematically proven) that it is possible for every single even integer.

See https://en.m.wikipedia.org/wiki/Goldbach%27s_conjecture

Answer 2

not possible for most odd numbers as 2 is the only prime even number.
e.g
33 = 31+2

Answer 3

Thanks Bogdan. Interesting info.