C comes with a host of functions for reporting the current time. The time() function returns the number of seconds elapsed since January 1, 1970, known as the Unix epoch. The value returned from the time() function is a time_t value. The localtime() function takes a time_t value and returns a tm structure that contains various time elements, such as the hour, minute, day of the month, and so on.
- [Instructor] The computer keeps track of the time … and so can your programs when you use … the C library's time functions. … The time function at line 8 fetches the time … in the time_t variable now declared at line 6. … The variables address is passed to the function, … so the value returned is in the same variable. … Both time and the time_t data type … require the time.h header file, … which is included in this code at line 2. … Build and run. … You were probably expecting … to see the current date and time, … but you are. … This value is known as the UNIX Epoch, … and it's the number of seconds that have ticked … since January 1, 1970. … Let's check out the last part of the value, 2182. … Run again. … And you see it's a new value, … a new number of seconds has elapsed. … Now you don't need to do all the math … to convert the Epoch time into the current time. … Instead this code uses the ctime function, … the end of line nine inside the printf statement. … This function is also prototyped in the time.h header file. …
- Working with arrays
- Building a structure
- Creating an array of structures
- Testing characters
- Working with strings in C
- Using pointers to manipulate data
- Manipulating files
- Using command-line arguments
- Working with time functions
Skill Level Intermediate
1. Arrays and Structures
2. Characters and Strings
4. Files and the Operating System
5. The Interesting and Extraordinary
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