Origin of C programming language
First of all BCPL language developed in 1967 by Martin Richard for developing the operating system and compilers.
This language helps in getting another language which is B language which was developed in 1970 by K. Thomson for 4 unix system development at Bell Laboratories.
With the help of this B language c language developed in 1972 by Dennis Ritchie. C language was developed for making Unix system more advanced but it become so much popular which is used or we can say it is a basic language of all languages.
C language is today widely used in:
a) developing operating systems
b) embedded system
c) real time operating system or Real Time systems
d) communication systems
C standard library:
It is prepackaged functions or rich collections of functions for performing common"Mathematical Calculations, String Manipulations, Character Manipulation, and Input / Output" and many other useful operations.Example:
sqrt(x):This c standard library function is used for calculating the square root of a value in this example the value is under the bracket which is x.
log10(x): This C standard library function is used to calculate the logarithm of x base 10.