C code files (with a.cpp extension) are not the only files commonly seen in C programs. The other type of file is called a header file. Header files usually have a.h extension, but you will occasionally see them with a.hpp extension or no extension at all. Mar 30, 2013 C Programming on the Mac L30 - Creating header files - Duration: 4:54. AppleProgramming 7,442 views. Jan 11, 2017 Here unsigned int is the number of milliseconds (remember 1 second = 1000 milliseconds). To use delay function in your program you should include the 'dos.h' header file which is not a part of standard C library. The sound(x) operator inputs an integer x.the ineger x should be signed before.and the fuction. Mar 28, 2013 You may be wondering how to add graphics.h in dev C. Dev C does not support BGI Graphics we have to include graphics library manually. Here are few steps you must follow before using graphics.h header file.
File Handling in C. File Handling concept in C language is used for store a data permanently in computer. Using file handling we can store our data in Secondary memory (Hard disk). Why use File Handling in C. For permanet storage. The transfer of input - data or output - data from one computer to another can be easily done by using files.
- The C Standard Library
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The time.h header defines four variable types, two macro and various functions for manipulating date and time.
Library Variables
C++ Using Header Files
Following are the variable types defined in the header time.h −
| Sr.No. | Variable & Description |
|---|---|
| 1 | size_t This is the unsigned integral type and is the result of the sizeof keyword. |
| 2 | clock_t This is a type suitable for storing the processor time. |
| 3 | time_t is This is a type suitable for storing the calendar time. |
| 4 | struct tm This is a structure used to hold the time and date. |
The tm structure has the following definition −
Library Macros
Following are the macros defined in the header time.h −
Header Files In Dev C++
| Sr.No. | Macro & Description |
|---|---|
| 1 | NULL This macro is the value of a null pointer constant. |
| 2 | CLOCKS_PER_SEC This macro represents the number of processor clocks per second. |
C++ Header Files Pdf
Library Functions
Following are the functions defined in the header time.h −
| Sr.No. | Function & Description |
|---|---|
| 1 | char *asctime(const struct tm *timeptr) Returns a pointer to a string which represents the day and time of the structure timeptr. |
| 2 | clock_t clock(void) Returns the processor clock time used since the beginning of an implementation defined era (normally the beginning of the program). |
| 3 | char *ctime(const time_t *timer) Returns a string representing the localtime based on the argument timer. |
| 4 | double difftime(time_t time1, time_t time2) Returns the difference of seconds between time1 and time2 (time1-time2). |
| 5 | struct tm *gmtime(const time_t *timer) The value of timer is broken up into the structure tm and expressed in Coordinated Universal Time (UTC) also known as Greenwich Mean Time (GMT). |
| 6 | struct tm *localtime(const time_t *timer) The value of timer is broken up into the structure tm and expressed in the local time zone. |
| 7 | time_t mktime(struct tm *timeptr) Converts the structure pointed to by timeptr into a time_t value according to the local time zone. |
| 8 | size_t strftime(char *str, size_t maxsize, const char *format, const struct tm *timeptr) Formats the time represented in the structure timeptr according to the formatting rules defined in format and stored into str. |
| 9 | time_t time(time_t *timer) Calculates the current calender time and encodes it into time_t format. |