CODEWITHSUNDEEP
c
Handysaur
Handysaur

Reputation: 1

Validate a date up to current time

i'm doing a program in c that needs to have random dates that have to be valid and after the current date. For the generation there aren't any problems at all. The only thing i can't do is to accept only the up to date dates.

I've already tried to firstly check if the date is valid and then to check if is greater than current date. Then i've tried to do the opposite but any of these solutions didn't worked.

This is the function that checks the date:

short dateControl( const unsigned short day, const unsigned short month, const unsigned short year, const int min_year, const int max_year, struct tm curTime)
{
    short correct = ZERO;

    if( (year >= curTime.tm_year) && (year <= max_year) ){
        if( (month >= 1) && (month <= 12) ){
            if( (day >= 1 && day <= 31) && (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) ){
                correct = ONE;
            }else if( (day >= 1 && day <= 30) && (month == 4 || month == 6 || month == 9 || month == 11) ){
                correct = ONE;
            }else if( (day >= 1 && day <= 28) && (month == 2) ){
                correct = ONE;
            }else if( day == 29 && month == 2 && (year % 400 == 0 ||(year % 4 == 0 && year % 100 != 0)) ){
                correct = ONE;
            }else{
                correct = ZERO;     
            }
        } else{
            correct = ZERO;         
            }
    }else{
        correct = ZERO;             
    }

if(correct == ONE){
    if( year > curTime.tm_year ){
            correct = ONE;
        }else if( year == curTime.tm_year ){
            if( month > curTime.tm_mon ){
                correct = ONE;
            }else if( month == curTime.tm_mon ){
                if( day > curTime.tm_mday ){
                    correct = ONE;
                }else if(day == curTime.tm_mday){
                    correct = ZERO;
                }else if(day < curTime.tm_mday){
                    correct = ZERO;
                }
            }else if( month < curTime.tm_mon ){
                correct = ZERO;
            }
        }
    }
}

    return correct;
}

This is the part where the date is generated

day = random_int(1, 31);
month = random_int(1, 12);
year = random_int(local->tm_year, local->tm_year + 1);
validDate = dateControl(tempTrip.dep_date.day, tempTrip.dep_date.month, tempTrip.dep_date.year, local->tm_year, (local->tm_year + 1), *local);
    while(validDate == ZERO){
    tempDriver.sub_date.day = random_int(1, 31);
    tempDriver.sub_date.month = random_int(1, 12);
    tempDriver.sub_date.year = random_int(local->tm_year, (local->tm_year + 1));
    validDate = dateControl(tempTrip.dep_date.day, tempTrip.dep_date.month, tempTrip.dep_date.year, local->tm_year, (local->tm_year + 1), *local);
    }
    }

I expect that if the generated date is 2/7/2019 and today is the 18/8/2019, the generated date needs to be discarded and another needs to be generated.

Upvotes: 0

Views: 73

Answers (1)

Brendan
Brendan

Reputation: 37232

i'm doing a program in c that needs to have random dates that have to be valid and after the current date. For the generation there aren't any problems at all. The only thing i can't do is to accept only the up to date dates.

The fact that you need to determine if the date is/isn't valid indicates that the way you're generating random dates is a problem.

Specifically, if you get the current time (using time()) and add a random positive value to it (while being careful to avoid overflow), and then convert the result into a date (e.g. using gmtime()); then you can guarantee that the random dates are valid and in the future without doing any checking and you can delete all of your dateControl() code.

Upvotes: 1

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