data structures using main(statement statement statement nfunction (statement statement statement nfunction (statement statement statement nfunctionn(statement statement statement nfigure structure of program of statements arranged according to specific meaningful sequence note that programmers can choose any name for functions it is not mandatory to write function function etc with an exception that every program must contain one function that has its name as main( identifiers and keywords every word in program is either an identifier or keyword identifiers identifiers are basically names given to program elements such as variablesarraysand functions they are formed by using sequence of letters (both uppercase and lowercase)numeralsand underscores following are the rules for forming identifier namesidentifiers cannot include any special characters or punctuation marks (like #$^?etc except the underscore "_there cannot be two successive underscores keywords cannot be used as identifiers the case of alphabetic characters that form the identifier name is significant for example'firstis different from 'firstand 'firstidentifiers must begin with letter or an underscore howeveruse of underscore as the first character must be avoided because several complier-defined identifiers in the standard library have underscore as their first character soinadvertently duplicated names may cause definition conflicts identifiers can be of any reasonable length they should not contain more than characters (they can actually be longer than but the compiler looks at only the first characters of the name keywords like every computer languagec has set of reserved words often known as keywords that cannot be used as an identifier all keywords are basically sequence of characters that have fixed meaning by conventionall keywords must be written in lower case letters table contains the list of keywords in table keywords in language auto break case char const continue default do double else enum extern float for goto if int long register return short signed sizeof static struct switch typedef union unsigned void volatile while basic data types data type determines the set of values that data item can take and the operations that can be performed on the item language provides four basic data types table lists the data typestheir sizerangeand usage for programmer the char data type is of one byte and is used to store single characters note that does not provide any data type for storing text this is because text is made up of individual characters you