\begin{verbatim}
#include <stdio.h>  // For the printf prototype
#include <string.h> // For the sscanf prototype
#include <stdlib.h> // For the exit prototype
#include <math.h>   // For the sin prototype

int main(int argc, char ** argv)
{
    int n = 40;
    int i;
    float x, y;

    if (argc == 2) {
        if (sscanf(argv[1], "n=%d", &n) != 1) {
            fprintf(stderr, "Usage: %s [n=...]\n", argv[0]);
            exit(1);
        }
    }

    for (i = 0; i < n; i++) { // Here is a comment.
        x = (float)i/n * 2.0 * M_PI;
        y = sin(x);
        printf("%3d %11.7f %11.7f\n", i, x, y);
    }

    return 0;
}
\end{verbatim}
