格式化NSTimeInterval

Question

// calculate elapsed time
NSTimeInterval elapsed = currentTime - startTime;

int mins = (int) (elapsed / 60.0);
elapsed -= mins * 60;
int secs = (int) (elapsed);
elapsed -= secs;
int fraction = elapsed * 10.0;

// update time label using format 0:00:0
returnTimeString = [NSString stringWithFormat:@"%u:%02u.%u",mins,secs,fraction];

这目前输出0:00.0。

我如何输出00:00.00，并让它每百分之一秒而不是十分之一秒递增？

Answer 1

returnTimeString = [NSString stringWithFormat:@"%02u:%05.2f",
    (int)(elapsed/60), fmod(elapsed, 60)];

Answer 2

您可以在格式说明符中使用0n对显示给n数字的数字长度进行零填充(其中n是正整数)，例如，

unsigned int seconds = elapsed;
unsigned int hundredths = (elapsed - seconds) * 100.0;
[NSString stringWithFormat:@"%02u:%02u.%02u", (seconds/60), (seconds%60), hundredths]