std::cout << "数値a 文字数:" << len1 << std::endl;
    std::cout << "数値b 文字数:" << len2 << std::endl;
    if( len1 == len2 ){
        std::cout << "文字数が一緒なので一桁ずつ判断します" << std::endl;        
        for( int i = 0; i < max_str; ++i ){
            if( str1[i] == str2[i] )
                continue;
            else if( str1[i] > str2[i] )
                std::cout << "a > b" << std::endl;
            else
                std::cout << "a < b" << std::endl;                
            break;
        }
    }else if( len1 > len2 )
        std::cout << "a > b" << std::endl;
    else
        std::cout << "a < b" << std::endl;

}

>>612
総書き直しすれば簡単