Library functions

Library Function

The c language comes with a number of library functions that are used to carry out various operations and calculations.

Example: standard input/ output operation function (printf(), scanf(), getchr(), putchar(), fopen, fclose() etc. which are included in stdio.h file)

Some function example used to perform operations on characters : tolower(), toupper(), isdigit(), islower(), isupper() etc.

Function that perform operation on strings:
strcpy(), strcmp(), strlen(), strrev() etc.

Function that perform mathematical calculations :
Trignometric functions: sin(), cos(), tan() etc.
logarithmic functions: log(), log10() etc.
exponential functions: exp()
absolute value function : abs()
square root sqrt() etc.