C-Character Array and String

Character Array and String,

INTRODUCTION
A string is a sequence of characters that is treated as a single data item. We have used strings in a number of examples in a number of example in the past. Any group of characters(except double quote sign) defined between double quotation marks is a string constant. Example:
“Man is obviously made to think.”

If we want to include a double quote in the string to be printed, then we may use it with a back slash as shown below.
“\” Man is obviously made to think,\” said Pascal.”

For example,
        printf (“\” Well Done !”\”);

will output the string

        ” Well Done !”

While the statement

        printf (” Well Done !”);

will output the string

        Well  Done!
Character  strings are often used to build meaningful and readable programs. The common operations performed on character string include:

1. Reading and writing strings
2. Combining string together
3. Copying one string to another
4. Comparing string for equality
5. Extracting a portion of a string
In this chapter we shall discuss these operations in detail and examine library function that implement them.

DECLARING AND INITIALIZING STRING VARIABLE
C does not support strings as a data type. However, it allows us to represent string as character arrays. in c therefore, a string variable is any validc variable name and is always declaredas an array of characters. The general form of declaration of a string variable is.

char string_name[ size ];

The size determine the number of characters in the string…. name. Some examples are:

char city[10];

char name[30];

Like numeric arrays, character arrays may be initialized when they are declared C permits a character array to be initialized in either of the following two forms

char city [9] = ” NEW YORK “;

char city [9] = {‘ N ‘,’ E ‘,’ W ‘,’  ‘ ,’ Y ‘,’ O ‘,’ R ‘,’ K ‘};

This will result in a compile time error. Also note that we cannot separate the initialization from declaration. This is

char str3[5];

str3 = “GOOD”;

is not allowed. Similarly,

char s1[4] = “abc”;

char s2[4];

s2 = s1; /* Error //
is not allowed. An array name cannot be used as the left operand of an assignment operator.