Solve isbn list

tests/exercises/isbn-list/solution/solution.cpp

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+#include <iostream>
+#include <string>
+#include <vector>
+#include <any>
+#include <cctype>
+
+bool is_isbn10(const std::string &code) {
+    // Helper function for computing ISBN-10 check digit
+    auto check_digit = [](const std::string &code) -> char {
+        int check = 0;
+        for (size_t i = 0; i < 9; ++i) {
+            check += (i + 1) * (code[i] - '0');
+        }
+        check %= 11;
+        return (check == 10) ? 'X' : (check + '0');
+    };
+
+    // Check whether given code contains 10 characters
+    if (code.length() != 10) return false;
+
+    // Check whether first nine characters of given code are digits
+    for (size_t i = 0; i < 9; ++i) {
+        if (!isdigit(code[i])) return false;
+    }
+
+    // Check the check digit
+    return check_digit(code) == code[9];
+}
+
+bool is_isbn13(const std::string &code) {
+    // Helper function for computing ISBN-13 check digit
+    auto check_digit = [](const std::string &code) -> char {
+        int check = 0;
+        for (size_t i = 0; i < 12; ++i) {
+            check += ((i % 2 == 0) ? 1 : 3) * (code[i] - '0');
+        }
+        check = (10 - (check % 10)) % 10;
+        return check + '0';
+    };
+
+    // Check whether given code contains 13 characters
+    if (code.length() != 13) return false;
+
+    // Check whether first twelve characters of given code are digits
+    for (size_t i = 0; i < 12; ++i) {
+        if (!isdigit(code[i])) return false;
+    }
+
+    // Check the check digit
+    return check_digit(code) == code[12];
+}
+
+template <typename T>
+bool is_isbn(const T &code, bool isbn13 = true) {
+    return isbn13 ? is_isbn13(code) : is_isbn10(code);
+}
+
+
+template <typename T>
+std::vector<bool> are_isbn(const std::vector<T> &codes) {
+    std::vector<bool> checks;
+    for (const auto &code : codes) {
+        if(code.type() != typeid(std::string)){
+            checks.push_back(false);
+            continue;
+        }
+        std::string isbn = std::any_cast<std::string>(code);
+        bool isbn13 = isbn.length() == 13;
+
+        checks.push_back(is_isbn(code, isbn13));
+    }
+    return checks;
+}
+
+template <typename T>
+std::vector<bool> are_isbn(const std::vector<T> &codes, bool isbn13) {
+    std::vector<bool> checks;
+    for (const auto &code : codes) {
+        checks.push_back(is_isbn(code, isbn13));
+    }
+    return checks;
+}