Jewels and stones

Jewels and stones is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Task

Create a function which takes two string parameters: 'stones' and 'jewels' and returns an integer.

Both strings can contain any number of upper or lower case letters. However, in the case of 'jewels', all letters must be distinct.

The function should count (and return) how many 'stones' are 'jewels' or, in other words, how many letters in 'stones' are also letters in 'jewels'.

Note that:

1. A lower case letter is considered to be different to its upper case equivalent for this purpose i.e. 'a' != 'A'.

2. The parameters do not need to have exactly the same names.

3. Validating the arguments is unnecessary.

So, for example, if passed "aAAbbbb" for 'stones' and "aA" for 'jewels', the function should return 3.

This task was inspired by this problem.

C

Translation of: Kotlin

<lang c>#include <stdio.h>

1. include <string.h>

int count_jewels(const char *s, const char *j) {

   int i, count = 0;
   for (i = 0; i < strlen(s); ++i) if (strchr(j, s[i])) ++count;
   return count;

}

int main() {

   printf("%d\n", count_jewels("aAAbbbb", "aA"));
   printf("%d\n", count_jewels("ZZ", "z"));
   return 0;

}</lang>

Output:

3
0

Kotlin

<lang scala>// Version 1.2.40

fun countJewels(s: String, j: String) = s.count { it in j }

fun main(args: Array<String>) {

   println(countJewels("aAAbbbb", "aA"))
   println(countJewels("ZZ", "z"))

}</lang>

Output:

3
0

Perl 6

<lang perl6>sub count-jewels ( Str $j, Str $s --> Int ) {

   my %counts_of_all = $s.comb.Bag;
   my @jewel_list    = $j.comb.unique;

   return %counts_of_all{ @jewel_list }.sum // 0;

}

say count-jewels 'aA' , 'aAAbbbb'; say count-jewels 'z' , 'ZZ';</lang>

Output:

3
0

Ring

<lang ring>

1. Project Jewels and Stones
2. Date 2018/04/25
3. Author Gal Zsolt (~ CalmoSoft ~)
4. Email <calmosoft@gmail.com>

jewels = "aA" stones = "aAAbbbb" see jewelsandstones(jewels,stones) + nl jewels = "z" stones = "ZZ" see jewelsandstones(jewels,stones) + nl

func jewelsandstones(jewels,stones)

       num = 0
       for n = 1 to len(stones)
            pos = substr(jewels,stones[n])
            if pos > 0
               num = num + 1
            ok
       next
       return num

</lang> Output:

3
0