time() functionality and tm structs w/ pointers

rat (2)
I am writing a Rolodex-type program to store information like birthday, phone number, etc. I have defined a Rolodex structure, and then declared an array of Rolodex structures, with one element in the array storing information for one person: 

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struct Rolodex
{
  struct tm Birthday;
  double AgeCalc;
};

Rolodex Entry[N_Records];


The data for the Birthday members are read in from a file; the AgeCalc value must be calculated. I then want to utilize the time() functionality to calculate a person's age based on current time. I have the code for getting current time,

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time_t now;
now = time(NULL);


but I need to create a time_t object from each Birthday member of the Rolodex array, which would allow me to use the diff() function - which wants 2 time_t data types. I *think* I need to create a pointer to Entry (or Entry[i].Birthday - I'm not certain which I need):

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Rolodex *ptrEntry;
ptrEntry = Entry;


and then use mktime() to return a time_t data type from the pointer (shown below just referencing a single element of the Rolodex array)

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time_t ref;
struct tm *temp2;
temp2 = &(ptrEntry[1].Birthday);
ref = mktime(temp2);


The print statement

 
 
cout << now << "\t" << ref << "\t" <<difftime(now,mktime(temp2));


returns:
1307078828 -1 1.30708e+09

which means the mktime() statement used to define ref doesn't like how I am pointing to my Birthday tm struct in assigning a value to temp2. I have been working on this for a while, but haven't made much progress. I'd like to define a good problem statement, get some feedback from you nice folks, and then work on it some more myself. I think I am close but my pointer/array syntax clumsiness is getting the best of me. Please let me know if you need any additional information. Thanks.



rat (2)
kbw, thanks for the links, but i do not think they address my specific question. i want to use diff() to calculate the difference in time between 2 time_t objects. i think i am generating the first time_t object (i.e., the current time) correctly, however the second needs to be generated from a struct tm ('Birthday' in my case). i do intend to use mktime() to convert the struct tm to a time_t type, but there are 2 issues.

first, mktime() does not receive a struct tm, it receives a pointer to a struct tm. if i just plug in the struct tm directly i get "error: cannot convert `tm' to `tm*' in assignment".

second, the struct tm is itself a member of the Rolodex structure i have defined. note i am dealing with an array of Rolodex structures, so i need to take this into account as well.

so my question is, how (if it is possible) do i point to a struct tm object that is a member of a defined
structure, which is, in turn, an element of an array? my best guess was

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time_t ref;
struct tm *temp2;
temp2 = &(ptrEntry[1].Birthday);
ref = mktime(temp2);


but when i plug 'ref' into mktime(), mktime() returns -1. suggestions on the pointer syntax?
dearvivekkumar (104)
Hey I have written one function which takes a string(since I am suing juce so i have used juce::String) which in format like "2011-06-02 14:06:07" this function returns a string(giving the sec/min/hr/day/monts/yr ago) like

May be you find it useful. But I say this is not that much accurate since(I have assumed that year has 365 days and months have 30 days)

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juce::String SPEditDictDialog::fun(juce::String &inTimeStr)
{
	/* Creates a tm struct for the two times to be compared. */
	struct tm *dicModTM = new tm;
	std::string inTimeStamp1 = inTimeStr.toCString();

	/* Parse the string to extract the indiviual time infromation from string and fill it into the tm struct. */
	dicModTM->tm_year	= atoi(inTimeStamp1.substr(0, 4).c_str());
	dicModTM->tm_mon 	= atoi(inTimeStamp1.substr(5, 2).c_str());
	dicModTM->tm_mday	= atoi(inTimeStamp1.substr(8, 2).c_str());
	dicModTM->tm_hour	= atoi(inTimeStamp1.substr(11, 2).c_str());
	dicModTM->tm_min	= atoi(inTimeStamp1.substr(14, 2).c_str());
	dicModTM->tm_sec	= atoi(inTimeStamp1.substr(17, 2).c_str());
	dicModTM->tm_year	= dicModTM->tm_year - 1900;
	dicModTM->tm_mon	= dicModTM->tm_mon  - 1;
	dicModTM->tm_mday	= dicModTM->tm_mday;

	/* Creates time_t variable from the tm struct. */
	time_t dictModTime = mktime(dicModTM);
	
	time_t presentTime;
	time(&presentTime);

	time_t timeDiff = presentTime - dictModTime;

	juce::String modTimeInfoStr;
	if(timeDiff >= 0 && timeDiff < 60)
	{
		modTimeInfoStr << (int)timeDiff;
		modTimeInfoStr +=	" secs ago";
	}
	else if(timeDiff >= 60 && timeDiff < 3600)
	{
		int min = (timeDiff / 60);
		int sec = (timeDiff % 60);
		
		modTimeInfoStr << min;
		if(min == 1)
			modTimeInfoStr +=	" min ";
		else
			modTimeInfoStr +=	" mins ";
		if(sec)
		{
			modTimeInfoStr << sec;
			if(sec == 1)
				modTimeInfoStr +=	" sec";
			else
				modTimeInfoStr +=	" secs";
		}
		modTimeInfoStr +=	" ago";
	}
	else if(timeDiff >= 3600 && timeDiff < 86400)
	{
		int hr = (timeDiff / 3600);
		int min = (timeDiff % 3600) / 60;
		
		modTimeInfoStr << hr;
		if(hr == 1)
			modTimeInfoStr +=	" hr ";
		else
			modTimeInfoStr +=	" hrs ";
		if(min)
		{ 
			modTimeInfoStr << min;
			if(min == 1)
				modTimeInfoStr +=	" min";
			else
				modTimeInfoStr +=	" mins";
		}
		modTimeInfoStr +=	" ago";
	}
	else if(timeDiff >= 86400 && timeDiff < 2592000)
	{
		int day = (timeDiff / 86400);
		int hr = (timeDiff % 86400) / 3600;
		
		modTimeInfoStr  << day;
		if(day ==1)
			modTimeInfoStr +=	" day ";
		else
			modTimeInfoStr +=	" days ";
		if(hr)
		{
			modTimeInfoStr << hr;
			if(hr == 1)
				modTimeInfoStr +=	" hr";
			else
				modTimeInfoStr +=	" hrs";
		}
		modTimeInfoStr +=	" ago";
	}
	else if(timeDiff >= 2592000 && timeDiff < 946080000)
	{
		int mon = (timeDiff / 2592000);
		int day = (timeDiff % 2592000) / 86400;
		
		modTimeInfoStr << mon;
		if(mon == 1)
			modTimeInfoStr +=	" month ";
		else
			modTimeInfoStr +=	" months ";
		if(day)
		{
			modTimeInfoStr  << day;
			if(day == 1)
				modTimeInfoStr +=	" day";
			else
				modTimeInfoStr +=	" days";
		}
		modTimeInfoStr +=	"ago";
	}
	else if(timeDiff >= 946080000)
	{
		int yr = (timeDiff / 31104000);
		int mon = (timeDiff % 31104000) / 2592000;
		
		modTimeInfoStr << yr;
		if(yr == 1)
			modTimeInfoStr +=	" yr ";
		else
			modTimeInfoStr +=	" yrs ";
		if(mon)
		{
			modTimeInfoStr << mon;
			if(mon == 1)
				modTimeInfoStr +=	" month";
			else
				modTimeInfoStr +=	" months";
		}
		modTimeInfoStr +=	" ago";
	}

	if(dicModTM)
	{
		delete dicModTM;
		dicModTM = NULL;
	}

	return modTimeInfoStr;
}
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