string in c language with example Androwep-Tutorials

String in c language androwep

The simplest of the console I/O functions are getchar( ), which reads a character from the keyboard, and putchar( ), which writes a character to the screen. The getchar( ) function waits until a key is pressed and then returns its value. The keypress is also automatically echoed to the screen. The putchar( ) function writes a character to the screen at the current cursor position.

Structure of String

#include <stdio.h> 
#include <ctype.h> 
int main(void) {   
  char ch;
  printf("Enter some text (type a period to quit).\n");  
  do {     
       ch = getchar();
       if(islower(ch)) 
           ch = toupper(ch);    
       else 
           ch = tolower(ch);
       putchar(ch);
     } while (ch != '.');
  return 0;
 }

A Problem with getchar( )

There are some potential problems with getchar( ). For many compilers, getchar( ) is implemented in such a way that it buffers input until ENTER is pressed. This is called line-buffered input; you have to press ENTER before any character is returned. Also, since getchar( ) inputs only one character each time it is called, line buffering may leave one or more characters waiting in the input queue, which is annoying in interactive environments.

#include <stdio.h> 
#include <conio.h> 
#include <ctype.h> 
int main(void) {  
   char ch;
   printf("Enter some text (type a period to quit).\n"); 
   do {     
       ch = getch();
       if(islower(ch)) 
           ch = toupper(ch);    
       else 
           ch = tolower(ch);
       putchar(ch);  
      } while (ch != '.');
 return 0;
 }

NOTE : At the time of this writing, when using Microsoft’s Visual C++ compiler, _getche( ) and _getch( ) are not compatible with the standard C input functions, such as scanf ( ) or gets( ). Instead, you must use special versions of the standard functions, such as cscanf( ) or cgets( ). You will need to examine the Visual C++ documentation for details.

Reading and Writing Strings

C language have more function for string. When we are using string function before we are use #include <string.h> header file. like as

1	strlen(string_name)	returns the length of string name.
2	strcpy(destination, source)	copies the contents of source string to destination string.
3	strcat(first_string, second_string)	concats or joins first string with second string. The result of the string is stored in first string.
4	strcmp(first_string, second_string)	compares the first string with second string. If both strings are same, it returns 0.
5	strrev(string)	returns reverse string.
6	strlwr(string)	returns string characters in lowercase.
7	strupr(string)	returns string characters in uppercase.

What is C string?

A string in C (also known as C string) is an array of characters, followed by a NULL character. To represent a string, a set of characters are enclosed within double quotes (“).

Why do we use string in C?

Unlike arrays we do not need to print a string, character by character. The C language does not provide an inbuilt data type for strings but it has an access specifier “%s” which can be used to directly print and read strings. You can see in the above program that string can also be read using a single scanf statement.

What is the function of string in C?

Commonly used String functions in C/C++ with Examples. Strings in C: Strings are defined as an array of characters. The difference between a character array and a string is the string is terminated with a special character ‘\0’. It will append copy of the source string in the destination string.