<< Chapter < Page Chapter >> Page >
Character classification functions
Category Functions
Letters isalpha( )
Lowercase letters islower( )
Uppercase letters isupper( )
Decimal digits isdigit( )
Hexadecimal digits isxdigit( )
Letters and decimal digits isalnum( )
Printable characters (including whitespace) isprint( )
Printable, non-whitespace characters isgraph( )
Whitespace characters isspace( )
Whitespace characters that separate words in a line of text isblank( )
Punctuation marks ispunct( )
Control characters iscntrl( )

The functions isgraph() and iswgraph() behave differently if the execution character set contains other byte-coded, printable, whitespace characters (that is, whitespace characters which are not control characters) in addition to the space character (' '). In that case, iswgraph() returns false for all such printable whitespace characters, while isgraph() returns false only for the space character (' ').

Case mapping functions

The functions listed in [link] yield the uppercase letter that corresponds to a given lowercase letter, and vice versa. All other argument values are returned unchanged.

Character conversion functions
Conversion Functions in ctype.h
Upper- to lowercase tolower( )
Lower- to uppercase toupper( )

String processing functions

A string is a continuous sequence of characters terminated by '\0', the string terminator character. The length of a string is considered to be the number of characters before the string terminator. Strings are stored in arrays whose elements have the type char or wchar_t. Strings of wide characters that is, characters of the type wchar_tare also called wide strings .

C does not have a basic type for strings, and hence has no operators to concatenate, compare, or assign values to strings. Instead, the standard library provides numerous functions, listed in

[link] to perform these and other operations with strings. The header string.h declares the functions for conventional strings of char. The names of these functions begin with str.

Like any other array, a string that occurs in an expression is implicitly converted into a pointer to its first element. Thus when you pass a string as an argument to a function, the function receives only a pointer to the first character, and can determine the length of the string only by the position of the string terminator character.

String-processing functions
Purpose Functions
Find the length of a string. strlen( )
Copy a string. strcpy( ), strncpy( )
Concatenate strings. strcat( ), strncat( )
Compare strings. strcmp( ), strncmp( ), strcoll( )
Transform a string so that a comparison of two transformed strings using strcmp( ) yields the same result as a comparison of the original strings using the locale-sensitive function strcoll( ). strxfrm( )
In a string, find:
- The first or last occurrence of a given character strchr( ), strrchr( )
- The first occurrence of another string strstr( )
- The first occurrence of any of a given set of characters strcspn( ), strpbrk( )
- The first character that is not a member of a given set strspn( )
Parse a string into tokens strtok( )
#include<stdio.h>#include<conio.h>#include<string.h>// You must declare the library string.h // to use functions strcpy, strcmp...void main() {char str1[10] = “abc”;char str2[10] = “def”;clrscr(); printf(“ str1: %s”,str1);printf(“\n str2: %s”,str2); printf(“\n strcmp(str1,str2) = %d”,strcmp(str1,str2));printf(“\n strcat(str1,str2) = %s”,strcat(str1,str2)); printf(“\n str1: %s”,str1);printf(“\n str2: %s”,str2); printf(“\n strcpy(str1,str2) = %s”,strcpy(str1,str2));printf(“\n str1: %s”,str1); printf(“\n str2: %s”,str2);strcpy(str1,”ab”); strcpy(str2,”abc”);printf(“\n strcmp(str1,str2) = %d”,strcmp(str1,str2)); getch();}
Got questions? Get instant answers now!

here is the sample session with the above program

str1: abc str2: defstrcmp(str1,str2) = -3 strcat(str1,str2) = abcdefstr1: abcdef str2: defstrcpy(str1,str2) = def str1: defstr2: def strcmp(str1,str2) = -3

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Introduction to computer science. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10776/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Introduction to computer science' conversation and receive update notifications?

Ask