introduced and used bigint datatype

src/big_int.hpp

@@ -0,0 +1,27 @@
+#ifndef BIG_INT_HPP
+#define BIG_INT_HPP
+
+#include <string>
+#include <array>
+
+#include "tl/expected.hpp"
+
+struct BigInt {
+
+  BigInt() : data() {}
+  virtual ~BigInt() {}
+
+  enum class eError : uint8_t { PARSE_ERROR };
+  static tl::expected<BigInt, eError> from_string(const std::string &str);
+
+  static BigInt from_int(uint64_t value);
+  std::string to_string() const;
+
+  friend bool operator == (const BigInt& rhs, const BigInt& lhs);
+private:
+  std::array<uint8_t,256> data;
+};
+
+bool operator==(const BigInt &rhs, const BigInt &lhs);
+
+#endif // #ifndef #ifndef BIG_INT_HPP