[justincormack]

It is possible to program C with a functional mindset, but the syntax does get in the way. The function syntax does not distinguish between parameters that are modified but you can by convention, and use of structs to bundle stuff up. You can pass function pointers liberally. In the end though the number of use cases for C is smaller now, and you should be able to avoid it for large projects and only use it for small pieces.

[spc476]

Actually, C89 can distinguish between parameters that are modifiable and those that are not. The syntax leaves a bit to be desired ("const foo_t x", "foo_t const x" and "const foo_t *const x" all have different semantics) but it can be done.