This category function is used to deal with single characters, including the category test of characters and the case conversion of characters.
Header file ctype.h
Function list
Detailed description of function category and function purpose
Is the character test alphanumeric?
Is that the letter isalpha?
Whether to control the character iscntrl.
Is it digital?
Can I display characters (except spaces)?
Can I display characters (including spaces)?
Is it a displayable character that is neither a space nor letters and numbers?
Whether this space is space or not.
Is the capital letter isupper?
Is the hexadecimal digit (0-9, A-F) character of 16 xdigital?
Character case conversion function is converted to uppercase letter toupper.
Convert to lowercase letter tolower
regionalization
Functions in this category are used to deal with language differences in different countries.
Header file local.h
Function list
Detailed description of function category and function purpose
Zone control zone setting setlocale
The number format convention queries the format conversion of the country's currency, date, time, etc.
mathematical function
This classification gives various mathematical calculation functions. It must be reminded that the data format in ANSI C standard does not conform to IEEE754 standard, but some C language compilers follow IEEE754 (for example, frinklin C5 1).
Header file math.h
Function list
Detailed description of function category and function purpose
Error condition handles domain error (the input parameter value of the function is not within the specified range)
Range error (the return value of the function is not within the specified range)
Trigonometric function anti-cosine function
Arc string asin
Inverse cheatan
Arctangent 2 atan2
Cosine cosine
Sine sine
Tangent tan
Hyperbolic function hyperbolic cosine cosine
Hyperbolic sine
Hyperbolic tangent function
Exponential and logarithmic exponential functions
Exponential decomposition function frexp
Product exponential function fdexp
natural logarithm
Logarithm 10, radix 10.
Floating-point decomposition function
Power function power function power
Square root function
Integer truncation, the lower bound of absolute value and remainder function is close to integer ceil.
Juedui wafer factory
Find the upper bound near the lower bound of integer.
Find the remainder
This classification function is used to jump code directly between different basis functions. Header file setjmp.h io.h
Function list
Detailed description of function category and function purpose
Save the calling environment setjmp
Resume calling environment longjmp
Signal processing
This classification function is used to handle the abnormal situation during the execution of the program.
Header file signal
Function list
Detailed description of function category and function purpose
Designated signal processing function signal
Send a lifting signal.
Variable parameter processing
This kind of function is used to realize variable basis functions such as printf and scanf.
Header file stdarg.h
Function list
Detailed description of function category and function purpose
Variable parameter access macro variable parameter start macro va_start
Variable parameter ending macro va_end
The variable parameter access macro accesses the next variable parameter macro va_arg.
Input-output function
This classification is used to handle various input and output devices, including files and consoles, and various functions are realized in a "stream" way.
Header file stdio.h
Function list
Detailed description of function category and function purpose
Document function
Delete file removal
Modify file name rename
Generate temporary file name tmpfile
Get temporary file path tmpnam
File access closed. File closed.
Refresh buffer fflush
opening file
Connect existing stream pointers and new files to freopen.
Set disk buffer setbuf
Set disk buffer setvbuf
Format input and output functions print format fprintf
Format input fscanf
Format output (console) printf
Format input (console) scan f
Format the output to the buffer sprintf
Enter sscanf format from the buffer.
Print format vfprintf
Print format vprintf
Print format vsprintf
The character input and output function inputs the character fgetc.
String input fgets
Character output fputc
String output fputs
Character input (console)
Character input (console) getchar
String input (console) acquisition
Character output (console)
Character output (console) putchar
String output (console) puts
Characters are output to the header ungetc of the stream.
Direct input output direct stream read operation
Direct stream write operation fwrite
The file location function gets the file location fgetpos.
File location moving search
File location setting offset
Get file location ftell
File location reset zero reminder
Error handling function error clearing clearerr
End of file judgment
File error detection
Get the error prompt string perror
utility function
This classification gives some functions that cannot be classified according to the above, but are necessary for programming.
Header file standard library
Function list
Detailed description of function category and function purpose
The string conversion function converts a string into an integer atoi.
Converts a string to a long integer.
Converts a string to a floating-point number strtod
Converts a string to a long integer.
Converts a string to an unsigned long integer.
Pseudo-random sequence generation function generates random number rand
Sets the starting value srand of the random function.
Memory management function allocates memory calloc
deallocating memory
Memory allocation malloc
Reassigned memory
Abort (environmental communication termination procedure)
Exit the program execution and clear the environment variable atexit.
Exit program execution exit
Read environment parameter getenv
The program is suspended and another program system is temporarily executed.
Search and sort tool method of bisection (data must be sorted) search.
Quick sort qsort
Absolute value abs of integer operation function
discrepancy
Get the base quotient and remainder of division operation.
Find the absolute value of length and shape the bottom laboratory
Find the quotient and remainder ldiv of long shaping division
The multibyte character function gets the number of bytes of multibyte characters.
Gets the number of bytes of multibyte characters mbtowc.
Multibyte character conversion
The string operation of multibyte characters converts multibyte strings into integer arrays mbstowcs.
Converts a multibyte string into a character array mcstowbs.
String processing
This classification function is used to merge and compare strings.
Header file string.h
Function list
Detailed description of function category and function purpose
String Copy Block Copy (target and source storage cannot overlap) memcpy
Block copy (target and source storage can overlap) Memory movement
String replication
Copy strncpy by string length
strcat_s
Connect the string strncat by length
String comparison function block comparison memcmp
String comparison strcmp
String comparison (non-English characters)
Compare strncmp and string by length
String conversion strxfrm
Character and string lookup character lookup memory
Character search structure
String lookup strcspn
String lookup strpbrk
String lookup strspn
String lookup strstr
String decomposition string
Miscellaneous function string setting memory set
Error string mapping string error.
Find the string length strlen
Date and time function
This category provides time and date processing functions.
Header file time.h
Function list
Detailed description of function category and function purpose
The time operation function obtains the processor clock.
Get the time difference difftime
Set time mktime
Get time time
Time conversion function gets the time of ASCII code.
Gets the time ctime represented by a string.
Gets the time strftime in the specified format.
Future development direction of function library
This section is used to explain how various types of function libraries will develop in the future.
Detailed description of serial number library category header file
1 error handling error number h
2 character processing ctype.h
3 regionalized local.h
4 mathematical function math.h
5 signal processing signal
6 input and output stdio.h
7 utility stdlib.h
8 string processing string.h