This document discusses handling character strings in C. It describes declaring string variables as character arrays with size equal to maximum length plus one for null character. Strings can be read using scanf with %s and written using printf with %s. Common string functions are described, including strcat to concatenate strings, strcmp to compare strings, strcpy to copy strings, and strlen to determine string length.

1. Handling of Character Strings
Topics
 Declaring String variables
 Reading String from terminal
 Writing String to Screen
 String handling Function

2. Declaring String Variables
 A string variable is any valid C variable
name and is always declared as an array.
The general form of declaration:
char string_name[size];
 Ex: char name[20];
 When the compiler assigns a character
string to a character array, it automatically
supplies a null character (‘0’) at the end of
the string. Therefore, the size should be
equal to the maximum number of characters
in the string plus one.

3. Reading and Writing Strings
 Input function scanf can be used with %s
format specification to read in a string of
characters. Ex:
char name[20];
scanf(“%s”,name);
 The printf function with %s format to print
strings to the screen. Ex:
printf(“%s”,name);
can be used to display the entire contents of
the array name.

4. String Handling functions
 strcat() Function: The strcat function joins
two strings together. It takes the following
form:
strcat(str1, str2);
 Here str1 and str2 are characters arrays. When
the function is executed, str2 is appended to str1
 If str1 and str2 contain “CSE” and “Discipline”
respectively then strcat(str1,str2) produce
“CSEDiscipline” to str1.

5. Continue…
 strcmp() Function: The strcmp function
compares two strings identified by the
arguments and has a value 0 if they are
equal. It takes the following form:
strcmp(str1, str2);
 Str1 and str2 may be string variables or string
constants.
 Ex: strcmp(name1,name2);
strcmp(name1, “Karim”);
strcmp(“Jon”,”Joy”);
If they are not equal then the different of ASCII
code of the different character is returned.

6. Continue…
 strcpy() Function: The strcpy function works
almost like a string-assigned operator. It
takes the following form:
strcpy(str1, str2);
 Here the contents of str2 is assigned to str1. str2
may be a character array variable or a string
constant.
 Ex: strcpy(name,”Jon”);
strcpy(name1,name2);

7. Continue…
 strlen() Function: The strlen function counts
and returns the number of characters in a
string. It takes the following form:
n = strlen(string);
 Here n is an integer variable which receives the
value of the length of the string.
 Ex: n=strlen(“CSE”); returns 3 to variable n.