This document discusses strings and string handling functions in C programming. It introduces strings as arrays of characters, and describes how to read and write strings using input/output functions. Examples are provided for programs that count characters in a string and reverse a string. Common string handling functions are explained, including strcmp(), strcpy(), strcat(), strlen(), and others. The document concludes with assignments for students to write programs implementing these string functions.

1. Introduction to Strings
Reading and Writing String
Examples
String Handling Functions
Assignement
Strings(character Array)
Abhineet Anand
Computer Science and Engg. Department
University of Petrolium and Energy Studies, Dehradun
November 20, 2014
Abhineet Anand Strings

2. Introduction to Strings
Reading and Writing String
Examples
String Handling Functions
Assignement
Introduction
A string is a one-dimensional array of Characters.
Abhineet Anand Strings

3. Introduction to Strings
Reading and Writing String
Examples
String Handling Functions
Assignement
Reading and Writing String
Arrays
A string can be read in or written out using the input/output
statements.
Reading string
scanf() with the %s format specfication.
gets() function
getchar() function several times.
Writing string
printf() with the %s format specfication.
puts() function
putchar() function several times.
Abhineet Anand Strings

4. Introduction to Strings
Reading and Writing String
Examples
String Handling Functions
Assignement
Examples
Write a program to accept a string and count the number of
characters in it and print the same.
Write a program to accept a string and reverse it, with
using any predefined string function.
Abhineet Anand Strings

5. Introduction to Strings
Reading and Writing String
Examples
String Handling Functions
Assignement
String Compare
String Copy and Concatenation
String Length and Comparing of n characters
Upper to Lower and appending of n characters
String Handling Functions
C Support a number of string handling functions.
Header File - string.h
Some of the string handling functions are
Strcmp()- function
The function compare two strings character by character
and return one of the three values-1,0,1
Syntax - strcmp(string1,string2);
-1 - if ASCII value of the charecter of first string is less than
of the second.
0 - if both strings are same
1 - if both strings are different
Example: p=strcmp("ABC","abc")
Here ASCII value of A(65)is less than a(97), so the result
will be -32.
Abhineet Anand Strings

6. Introduction to Strings
Reading and Writing String
Examples
String Handling Functions
Assignement
String Compare
String Copy and Concatenation
String Length and Comparing of n characters
Upper to Lower and appending of n characters
String Copy and Concatenation
Strcpy()- function
The function used to copy one string to the other.
Syntax - strcpy(string1,string2)
The Content on string1 will be overwritten by content of
string2.
Strcat()- function
The function used to concatenate.
Syntax - strcat(string1,string2)
String string2 is appended to the end of string1.
Abhineet Anand Strings

7. Introduction to Strings
Reading and Writing String
Examples
String Handling Functions
Assignement
String Compare
String Copy and Concatenation
String Length and Comparing of n characters
Upper to Lower and appending of n characters
String Length and Comparing of n characters
Strlen()- function
The function returns the numbers of characters in the string.
The string length does not include the’
0’(null) character.
Syntax - strcpy(string1)
string1 is one dimension array of characters.
Strncmp()- function
The function used to compare the first n character of string.
Syntax - strncmp(string1,string2,n)
-1 - if ASCII value of the charecter of first string is less than
of the second.
0 - if both strings are same
1 - if both strings are different
Abhineet Anand Strings

8. Introduction to Strings
Reading and Writing String
Examples
String Handling Functions
Assignement
String Compare
String Copy and Concatenation
String Length and Comparing of n characters
Upper to Lower and appending of n characters
Upper to Lower and appending of n characters
Strlwr()- function
The function is used to convert any uppercase letters in a
string to its equivalent lowercase.
Syntax - strlwr(string1)
string1 is one dimension array of characters.
Strncat()- function
The function used to append first n characters of the
second string at the end of the first string.
Syntax - strncat(string1,string2,n)
Strchr()- function
The function seraches for for specified character in a given
string.
Returns NULL if the desired character is not found in the
string.
Syntax - strncat(string, desired-char)
Abhineet Anand Strings

9. Introduction to Strings
Reading and Writing String
Examples
String Handling Functions
Assignement
Assignemnt
Write program to implement all the string function we have
discussed in the class.
Write a program to accept a string and count the number of
vowels and consonant in it.
Write a program to accept a line of text and display the
number of times each character appears in the text.
Abhineet Anand Strings

10. Introduction to Strings
Reading and Writing String
Examples
String Handling Functions
Assignement
THANK YOU
Abhineet Anand Strings