#include <iostream>
#include <exception>
#include <limits>
using namespace std;

class OutOfRangeException : public exception
{
public:
    OutOfRangeException()
        :exception()
    {}

public:
    OutOfRangeException(const char* const & what)
        :exception(what)
    {}

public:
    OutOfRangeException(const OutOfRangeException& rhs)
        :exception(rhs)
    {}
};

class FormatException : public exception
{
public:
    FormatException()
        :exception()
    {}

public:
    FormatException(const char* const & what)
        :exception(what)
    {}

public:
    FormatException(const FormatException& rhs)
        :exception(rhs)
    {}
};

int ParseInt(const char* str)
{
    static const int BASE = 10;
    int value = 0;
    int sign = 1;

    if (!*str) {
        throw FormatException("Passed string is not in a valid format.");
    }

    for (const char* p = str; *p; ++p) {
        switch (*p) {
            case '+': case '-':
                // check that we are at the beginning of the string
                if (p != str) {
                    throw FormatException("Passed string is not in a valid format.");
                }

                if (*p == '-') {
                    sign = -1;
                }

                break;

            case '0': case '1': case '2': case '3': case '4':
            case '5': case '6': case '7': case '8': case '9':
                // check range limits
                if (value > numeric_limits<int>::max() / BASE) {
                    throw OutOfRangeException("Value range overflow.");
                }

                // add digit
                value = value * BASE + (*p - '0');
                break;

            default:
                throw FormatException("Passed string is not in a valid format.");
                break;
        }
    }

    return value * sign;
}

int main()
{
    try {
        cout << ParseInt("1") << endl;
    } 
    catch (exception& ex) {
        cout << ex.what() << endl;
    }
}