Question

I need to get number of character in array.

const char myarray[5] = {'0', 'a', 'e', 'f', 'c'}; // Create array of char
int number=0; // Create variable
number = getposition(myarray, 'f'); // Now number equals to 3
number = getposition(myarray, 'z'); // -1, because array doesn't have this char

My task is easy because array don’t have repeating characters (for example, it can’t be smth like this: {‘a’, ‘1’, ‘f’, ‘a’}). How can I do it?

Answer 1

A little bit more C++:

#include <algorithm>

int getposition(const char *array, size_t size, char c)
{
     const char* end = array + size;
     const char* match = std::find(array, end, c);
     return (end == match)? -1 : (match-array);
}

A lot more C++:

template <typename T, size_t N>
int getposition(const T (&array)[N], const T c)
{
     const T* match = std::find(array, array+N, c);
     return (array+N==match)? -1 : std::distance(array, match);
}

Bonus C++11/C++11 update

#include <algorithm>
#include <iterator>

template <typename Range, typename T>
size_t index_of(Range const& range, T const& c) {
    using std::begin;
    using std::end;

    auto b = begin(range), e = end(range);
    auto match = std::find(b, e, c);

    return (e==match)? -1 : std::distance(b, match);
}

Bonus C++17 update

Here, the original question gets direct support in std::string_view:

Live On Coliru

#include <string_view>
using namespace std::string_view_literals;

int main() {
    return "hello"sv.find('e');
}