CODEWITHSUNDEEP
c++
venkysmarty
venkysmarty

Reputation: 11441

error c2440 error when overloading output operator

I am compiling following code and getting following error. How to fix this? Thanks for your help.

error C2079: 'issline' uses undefined class 'std::basic_istringstream<_Elem,_Traits,_Alloc>' 1> with 1>
[ 1> _Elem=char, 1>
_Traits=std::char_traits, 1> _Alloc=std::allocator 1> ] 1>d:\technical\c++study\readparsing\readparsing\main.cpp(49) : error C2440: 'initializing' : cannot convert from 'std::string' to 'int' 1> No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called 1>d:\technical\c++study\readparsing\readparsing\main.cpp(51) : error C2678: binary '>>' : no operator found which takes a left-hand operand of type 'int' (or there is no acceptable conversion) 1>
d:\technical\c++study\readparsing\readparsing\timestamp.h(31): could be 'std::istream &operator >>(std::istream &,TimeStamp &)' 1>
while trying to match the argument list '(int, TimeStamp)'

I have following code in TimeStamp.h

#ifndef __TIMESTAMP_
#define __TIMESTAMP_

#include <iostream>

struct DateTime
{
    unsigned int dwLowDateTime;
    unsigned int  dwHighDateTime;
};


class TimeStamp 
{
public:
    TimeStamp()
    {
        m_time.dwHighDateTime = 0;
        m_time.dwLowDateTime = 0;
    }

    TimeStamp& operator = (unsigned __int64 other)
    {
        *( unsigned __int64*)&m_time = other;
        return *this;
    }
private:
    DateTime        m_time;
};

std::istream& operator >> (std::istream& input, TimeStamp& timeStamp);

#endif

In main.cpp I have following

#include <iostream>
#include <algorithm>
#include <string>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

#include "TimeStamp.h"

std::istream& operator >> (std::istream& input, TimeStamp& timeStamp)
{
    // 1.
    // use regular stream operator parsing technique to parse individual integer x values (separated in the form "xxxx-xx-xx xx:xx:xx.xxx")
    // for year, month, day, hour, minute, seconds, mseconds
    unsigned int year;
    unsigned int month;
    unsigned int day;
    unsigned int hour;
    unsigned int minute;
    unsigned int seconds;
    unsigned int milliSeconds;
    char dash;
    char colon;

    input >> year >> dash >> month >> dash >> day >> hour >> colon >> minute >> colon >> seconds >> colon >> milliSeconds;

    cout << "Time stamp opeator is called " << std::endl;

    // 2.
    // code to be written.

    return input;
}



int main () {

    std::string dateTime = "2012-06-25 12:00:10.000";

    TimeStamp myTimeStamp;

    std::istringstream issline(dateTime);

    issline >> myTimeStamp;


   return 0;
}

Upvotes: 0

Views: 340

Answers (2)

MadScientist
MadScientist

Reputation: 3460

You need to 

#include <sstream>

in main.cpp. The error message says that you are using a class that has been (forward) declared but not defined. Usually that means you are missing an include.

Note that #include <iosfwd> would suffice in TimeStamp.h instead of #include <iostream>

Upvotes: 1

mathematician1975
mathematician1975

Reputation: 21351

I think you need to #include <sstream> to use istringstream.

Upvotes: 3

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