You can program a non-recursive Fibonacci function in C using a iterative approach with a for loop. Here's a simple and straightforward example: ```c #include void fibonacci(int n) { int t1 = 0, t2 = 1, nextTerm; // Displaying the first two terms printf("Fibonacci Series: %d, %d, ", t1, t2); nextTerm = t1 + t2; for (int i = 3; i <= n; ++i) { printf("%d, ",nextTerm); t1 = t2; // Updating the terms for the next round t2 = nextTerm; nextTerm = t1 + t2; // Calculating the next term } } int main() { int n; printf("Enter the number of terms: "); scanf("%d", &n); fibonacci(n); return 0; } ``` This program first displays the first two terms of the Fibonacci sequence. Then, it enters the loop where `nextTerm` is calculated as the sum of `t1` and `t2`. Then, `t1` and `t2` are updated for the next round and the next term is calculated again. This process continues until it reaches the nth term. The non-recursive nature of the function lies in the loop; instead of calling itself to calculate the next term, it simply uses the previously calculated terms. This way, the program avoids the extra computational effort and possible stack overflows associated with recursive functions. Remember to always include proper error checks and edge cases handling, such as when n is less than 1.

Sure, here is a simple and straight-to-the-point way to program a Fibonacci function non-recursively in C: ```c #include void fib(int n) { int t0 = 0, t1 = 1, nextTerm; for (int i = 1; i <= n; ++i) { printf("%d, ", t0); nextTerm = t0 + t1; t0 = t1; t1 = nextTerm; } } int main() { int n; printf("Enter the number of terms: "); scanf("%d", &n); fib(n); return 0; } ``` The `fib` function generates the Fibonacci sequence up to `n` terms. `t0` and `t1` store the first two terms (0 and 1) of the sequence. The loop starts from 1 since the first two terms are hardcoded. In each iteration of the loop, the program displays the value of `t0`, calculates the next term as the sum of `t0` and `t1`, and then updates `t0` and `t1` to be ready for the next term. This is repeated until the desired number of terms have been printed. The `main` function receives user input and calls the `fib` function. If you wish to return the `nth` Fibonacci number instead of printing the sequence, consider the following function: ```c int fib(int n) { int t0 = 0, t1 = 1, nextTerm; for (int i = 1; i <= n; ++i) { nextTerm = t0 + t1; t0 = t1; t1 = nextTerm; } return t0; } ``` This adjustment only returns the `nth` Fibonacci number. Remember, this method uses a loop to calculate and consequently generate each Fibonacci number, which is what makes it non-recursive. This is considerably more efficient than its recursive counterpart, especially for larger values of `n`, as it avoids the overhead of repeated function calls and takes constant O(1) space complexity (since it only requires 3 integer variables).