Task: Partition an integer x into n primes
C: #include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

typedef struct bit_array_tag {
    uint32_t size;
    uint32_t* array;
} bit_array;

bool bit_array_create(bit_array* b, uint32_t size) {
    uint32_t* array = calloc((size + 31)/32, sizeof(uint32_t));
    if (array == NULL)
        return false;
    b->size = size;
    b->array = array;
    return true;
}

void bit_array_destroy(bit_array* b) {
    free(b->array);
    b->array = NULL;
}

void bit_array_set(bit_array* b, uint32_t index, bool value) {
    assert(index < b->size);
    uint32_t* p = &b->array[index >> 5];
    uint32_t bit = 1 << (index & 31);
    if (value)
        *p |= bit;
    else
        *p &= ~bit;
}

bool bit_array_get(const bit_array* b, uint32_t index) {
    assert(index < b->size);
    uint32_t bit = 1 << (index & 31);
    return (b->array[index >> 5] & bit) != 0;
}

typedef struct sieve_tag {
    uint32_t limit;
    bit_array not_prime;
} sieve;

bool sieve_create(sieve* s, uint32_t limit) {
    if (!bit_array_create(&s->not_prime, limit + 1))
        return false;
    bit_array_set(&s->not_prime, 0, true);
    bit_array_set(&s->not_prime, 1, true);
    for (uint32_t p = 2; p * p <= limit; ++p) {
        if (bit_array_get(&s->not_prime, p) == false) {
            for (uint32_t q = p * p; q <= limit; q += p)
                bit_array_set(&s->not_prime, q, true);
        }
    }
    s->limit = limit;
    return true;
}

void sieve_destroy(sieve* s) {
    bit_array_destroy(&s->not_prime);
}

bool is_prime(const sieve* s, uint32_t n) {
    assert(n <= s->limit);
    return bit_array_get(&s->not_prime, n) == false;
}

bool find_prime_partition(const sieve* s, uint32_t number, uint32_t count,
                          uint32_t min_prime, uint32_t* p) {
    if (count == 1) {
        if (number >= min_prime && is_prime(s, number)) {
            *p = number;
            return true;
        }
        return false;
    }
    for (uint32_t prime = min_prime; prime < number; ++prime) {
        if (!is_prime(s, prime))
            continue;
        if (find_prime_partition(s, number - prime, count - 1,
                                 prime + 1, p + 1)) {
            *p = prime;
            return true;
        }
    }
    return false;
}

void print_prime_partition(const sieve* s, uint32_t number, uint32_t count) {
    assert(count > 0);
    uint32_t* primes = malloc(count * sizeof(uint32_t));
    if (primes == NULL) {
        fprintf(stderr, "Out of memory\n");
        return;
    }
    if (!find_prime_partition(s, number, count, 2, primes)) {
        printf("%u cannot be partitioned into %u primes.\n", number, count);
    } else {
        printf("%u = %u", number, primes[0]);
        for (uint32_t i = 1; i < count; ++i)
            printf(" + %u", primes[i]);
        printf("\n");
    }
    free(primes);
}

int main() {
    const uint32_t limit = 100000;
    sieve s = { 0 };
    if (!sieve_create(&s, limit)) {
        fprintf(stderr, "Out of memory\n");
        return 1;
    }
    print_prime_partition(&s, 99809, 1);
    print_prime_partition(&s, 18, 2);
    print_prime_partition(&s, 19, 3);
    print_prime_partition(&s, 20, 4);
    print_prime_partition(&s, 2017, 24);
    print_prime_partition(&s, 22699, 1);
    print_prime_partition(&s, 22699, 2);
    print_prime_partition(&s, 22699, 3);
    print_prime_partition(&s, 22699, 4);
    print_prime_partition(&s, 40355, 3);
    sieve_destroy(&s);
    return 0;
}

VB: 
    dim p(),a(32),b(32),v,g: redim p(64)
    what="99809 1  18 2  19 3  20 4  2017 24  22699 1-4  40355 3"
    t1=split(what,"  ")
    for j=0 to ubound(t1)
        t2=split(t1(j)): x=t2(0): n=t2(1)
        t3=split(x,"-"): x=clng(t3(0))
        if ubound(t3)=1 then y=clng(t3(1)) else y=x
        t3=split(n,"-"): n=clng(t3(0))
        if ubound(t3)=1 then m=clng(t3(1)) else m=n
        genp y 
        for g=x to y
            for q=n to m: part: next 
        next 
    next 

sub genp(high)
    p(1)=2: p(2)=3: c=2: i=p(c)+2
    do 
        k=2: bk=false
        do while k*k<=i and not bk 
            if i mod p(k)=0 then bk=true
            k=k+1
        loop 
        if not bk then
            c=c+1: if c>ubound(p) then redim preserve p(ubound(p)+8)
            p(c)=i
        end if
        i=i+2
    loop until p(c)>high 
end sub 

sub getp(z)
    if a(z)=0 then w=z-1: a(z)=a(w)
    a(z)=a(z)+1: w=a(z): b(z)=p(w)
end sub 

function list()
    w=b(1)
    if v=g then for i=2 to q: w=w&"+"&b(i): next else w="(not possible)"
    list="primes: "&w
end function 

sub part()
    for i=lbound(a) to ubound(a): a(i)=0: next 
    for i=1 to q: call getp(i): next 
    do while true: v=0: bu=false
        for s=1 to q
            v=v+b(s)
            if v>g then
                if s=1 then exit do
                for k=s to q: a(k)=0: next 
                for r=s-1 to q: call getp(r): next 
                bu=true: exit for
            end if
        next 
        if not bu then
            if v=g then exit do
            if v<g then call getp(q)
        end if    
    loop
    wscript.echo "partition "&g&" into "&q&" "&list
end sub