Santosh Dahal

what everybody ought to know about string in c.

String in C

You will be able to :

Define string

Declaration of String

Initialization of String

Use string handling function

String

In C programming, array of character are called strings. A string is terminated by null character /0.

Array is the collection of similar data under common name.

A common name is the name of string or array.

For example:

char stringname  = "Hello";

Here stringname is common name .We will study String Decleration below Section.

C compiler represent above string as below image (string representation)

c-string-representation

Declaration of String

It is declared as:

char string_name[size];

E.g: char name[10];

Strings can also be declared using pointer.

char *p

Initialization of String

It can be initialized when they are declared

char c[]="abcd";
     OR,

char c[5]="abcd";

     OR,

char c[]={'a','b','c','d','\0'};

     OR;

char c[5]={'a','b','c','d','\0'}; .

String can also be initialized using pointers

char *c="abcd";

String Handling Function

There are different libraries or built-in function in C for string manipulation.These function are defined in header file <string.h>

All string manipulation can be done manually by the programmer but, this makes programming complex and large.

To solve this, the C supports a large number of string handling functions.

strlen()  -  Calculates the length of string

strcpy() -   Copies a string to another string

strcat()  -  Concatenates(joins) two strings

strcmp() -   Compares two string

strlwr()  -  Converts string to lowercase

strupr()  -  Converts string to uppercase

1. strlen():

This is used to return the length of string

It returns the number of characters in the string without including null character

Syntax:

integer_variable = strlen(string);

2. strcpy() :

It copies one string to another

Syntax:

strcpy(destination_string , source_string);

e.g strcpy(a,b) i.e the content of b is copied to a

3. strcat():

It joins to strings together

It stores the content of second string at the end of the first one.

E.g: strcat (string1 , string2  );

i.e string1 = string1 + string2;

4. strcmp():

It compares two string

It takes two strings as parameters and returns the integer value.

  0 if both string are same

  less than zero if  the first string is less than the second one.

  Greater than zero if the first string is more than the second

5. strrev () :

It is used to reverse all character of string except the null character

Syntax:

    strrev ( string );

    E.g strrev(str) i.e it reverses the characters in string str and stores the reversed string in the str