Here's the equivalent Fibonacci function in C:
```c
int fib(int n) {
    int baseCase1 = 0;
    int baseCase2 = 1;
    int current = 0;

    if (n == 0) {
        return baseCase1;
    }

    if (n == 1) {
        return baseCase2;
    }

    int prev1 = baseCase1;
    int prev2 = baseCase2;

    for (int i = 2; i <= n; i++) {
        current = prev1 + prev2;
        prev1 = prev2;
        prev2 = current;
    }

    return current;
}
```
Note that this implementation uses an iterative approach instead of a recursive one, which is more efficient and generally preferred. It also uses a loop to calculate the Fibonacci sequence instead of function calls.
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