Arithmetic functions

abs   returns absolute value of the integer

cos   calculates cosine

cosh  calculates hyperbolic cosine

exp     raises the exponential e to the xth power

fabs    finds absolute value

floor    find largest integer less than or equal to argument

fmod   finds folating point reminder

hypot   calculates hypotunese of right triangle

log       calculates natural algorithm.

log10  calculates base 10 algoritm

modf    breaks down argument into integer and fractional parts

pow       calculates a value raised to power

sin        calculates sine

sinh      calculates hyperbolic sine

sqrt        finds square root

tan         calculates tangent

tanh       calculates hyperbolic tangents

Character classification functions

isalnum      tests for alphanumeric character

isalpha       tests for alphabetic character

isdigit          tests for decimal digit

islower        tests for lowercase characters

isspace       tests for white space character

isupper        tests for uppercase character

isxdigit          tests for hexadecimal digits

tolower         tests characters and converts to lower if its in uppercase

toupper        tests a characters and coverts to upper if its in lowercase

Data conversion functions

atof              converts string to float

atoi              converts string to int

atol              converts string to long

ecvt              converts double to string

fcvt               converts double to string

gcvt              converts double to string

itoa              converts int to string

ltoa              converts long to string

strtod          converts string to double

strtol           converts string to long integer

strtoul         converts string to unsigned long integer

ultoa           converts unsigned long to string

Searching and sorting functions

bsearch          for binary search

lfind                 for linear search for given value

qsort               for quick sort

File handling functions

remove          Delete files

rename         Renames files

unlink            Delete files

Disk I/O functions

absread             reads absolute disk sectors

abswrite             writes absolute write sectors

biosdisk            performs bios disk services

getdisk              gets current drive number

setdisk              sets current disk drive

Memory allocation functions

calloc           allocates a block of memory

farmalloc     allocates memory from far heap

farfree          frees a block from far heap

free               frees a block allocates with malloc

malloc         allocates a block of memory

realloc         reallocates a block of memory