I got two methods to solve the the live time.it’s absolutely that my first codes are wrong , I have calculated my live time.I paste my two codes here, the first"i have been alive is …" is wrong, and the last “i have been alive …” is right. I want to know, what’s wrong with my first codes?
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this is the codes below:
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.#import <Foundation/Foundation.h>
int main(int argc, const char * argv[]) {
@autoreleasepool {
NSDate *borntime = [NSDate dateWithTimeIntervalSinceReferenceDate: 1987-12-30];
NSDate *now = [NSDate date];
unsigned int seconds = [now timeIntervalSinceDate:borntime];
NSLog(@“I have born %u seconds”,seconds);
// insert code here…
NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setYear:1987];
[comps setMonth:12];
[comps setDay:30];
[comps setHour:0];
[comps setMinute:0];
[comps setSecond:0];
NSCalendar *g = [[NSCalendar alloc]initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDate *date0fBirth = [g dateFromComponents:comps];
NSLog(@"Jack's date of birth is %@.",date0fBirth);
NSLog(@"Hello, World!");
NSDate *nowagain = [NSDate date];
unsigned int secondsagain = [nowagain timeIntervalSinceDate:date0fBirth];
NSLog(@"I have born %u seconds",secondsagain);
}
return 0;
}
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and this is the part after running:
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.2016-06-14 08:16:17.939 exercise14_7[454:11155]
I have born 487554232 seconds
2016-06-14 08:16:17.945 exercise14_7[454:11155] Jack’s date of birth is 1987-12-29 16:00:00 +0000.
2016-06-14 08:16:17.945 exercise14_7[454:11155] Hello, World!
2016-06-14 08:16:17.946 exercise14_7[454:11155]
I have born 898071377 seconds
Program ended with exit code: 0