C Implementation of Problem 1

View source code here on GitHub!

Includes

• "iterator.h"

• "macros.h" (implicitly, via digits.h)

• "iterator.h" (implicitly, via digits.h)

• "math.h" (implicitly, via digits.h & if compiled on PCC)

• <inttypes.h>

• <stdint.h>

• <stdio.h>

• <stdbool.h> (implicitly, via digits.h)

• <stdlib.h> (implicitly, via digits.h & if not compiled on PCC)

• <math.h> (implicitly, via digits.h & if not compiled on PCC)

Solution

uint32_t p0001()

int main(int argc, char const *argv[])

Note

This function is only present in the Python test runner, or when compiling as a standalone program. It is not present when compiling for the Unity test runner.

/**
 * Project Euler Problem 1
 *
 * I know that this could be done faster with a traditional for loop, but I wanted
 * to see if iterators were reasonably possible in C, since it makes the prime
 * number infrastructure a lot easier to set up.
 *
 * Problem:
 *
 * If we list all the natural numbers below 10 that are multiples of 3 or 5, we
 * get 3, 5, 6 and 9. The sum of these multiples is 23.
 *
 * Find the sum of all the multiples of 3 or 5 below 1000.
 */
#ifndef EULER_P0001
#define EULER_P0001
#include <stdint.h>
#include <inttypes.h>
#include <stdio.h>
#include "include/macros.h"
#include "include/iterator.h"

uint32_t EMSCRIPTEN_KEEPALIVE p0001() {
    uint32_t answer = 0;
    counter c = counter3(0, 1000, 3);
    while (!c.exhausted)
        answer += next(c);
    c = counter3(0, 1000, 5);
    while (!c.exhausted)
        answer += next(c);
    c = counter3(0, 1000, 15);
    while (!c.exhausted)
        answer -= next(c);
    return answer;
}

PROGRAM_TAIL("%" PRIu32, p0001)
#endif

Tags: c-iterator, divisibility