string.h
    strlen()    : Computes the length of a cstring
    strcpy()    : Copies one cstring into another cstring
    strncpy()   : Copies n characters from one cstring into another cstring
    strcat()    : Concatenates one cstring with another
    strncat()   : Concatenates n characters from one cstring with another cstring
    strcmp()    : Compares two cstrings 
    strncmp()   : Compares n characters in two cstrings
    strchr()    : Computes the position of a character in a string
    strspn()    : Computes the length of the portion of a cstring that is composed of the characters from a second cstring
    strcspn()   : Computes the length of the portion of a cstring that is not composed of any character from a second cstring
    strdup()    : Allocates necessary memory and duplicates a cstring into newly allocated memory
    strtok()    : Breaks a cstring into tokens based on given delimiter characters in another cstring
    memset()    : Sets the value of all characters in a cstring
    memcpy()    : Copies the bytes from one area of memory into another non-overlapping area of memory
    memmove()   : Copies the bytes from one area of memory into another area of memory (two areas can overlap with each other)

stdlib.h
    exit()	: Terminates a process
    malloc()    : Allocates memory dynamically
    calloc()    : Allocates memory dynamically
    free()      : Releases dynamically allocated memory
    atoi()      : Converts a cstring into an integer
    strtol()    : Converts a cstring into a long integer
    strtoul()   : Converts a cstring into an unsigned long integer
    strtoll()   : Converts a cstring into a long long integer
    strtof()    : Converts a cstring int a float
    strtod()    : Converts a cstring into a double

stdio.h
    scanf()	: Reads formatted data from standard input (keyboard)
    printf()    : Prints a formatted output onto the screen
    sprintf()   : Prints a formatted output into a cstring buffer

math.h
    pow()       : Computes the power of a number, e.g., 2^3