Question

Answer the following question

1. What basic requirements of a C program are there ?

2. What basic requirements of Identifiers (variable name) are there?

3. Explains what data types are and how they are used to classify the value of a variable in a programming language.

4. What is Variable? What should be done before you use a variable?

Answer 1

1)

C is a general purpose programming language developed by Dennies Ritchie for Bell labs. As any other programing language'C' program also have some basic requiremnet to function properly

• We must have installed a c compiler into your machine becouse C is a high level language inorder to execute it by the processor we need a compiler which convert it to machine codes
• A c program typically contains a pre-processor directive statement at the beginning.Such statement are begin with a '#' symbol ,they are called header files.All basic functions such as input and outputs operations are defined in some header files hence header file are a basic requirement of a c program
• C programs is a collection of functions.It contain a main() function and may or maynot with user defined functions.C compiler starts execution from main() functions hence every C program must contain the main() function

2)

• An identifier can contain only letters (smmal and capitals), numbers and underscore
• Use of keywordds as identifiers are prohibited
• The first letter of identifier must be letter or underscore
• Identifiers should be unique

(In some OS ,ANSI C recoganize only the first 32 characters on the variable name hence varaible name should be less than it in length)

3)

Data types is actually the classification of variables according to the data it can store or the operations which can done on it.Data types are categorised as built-in and user defined

Built in data types in C are

• char :A basic data type which can store a single character(need one byte of memory)
• int : used to store integer type data (need two byte of memory)
• float :used to store decimal numbers (single precision)
• double it ios used to store numbers with double precision

So in C programming we have to use the apropriate variable to store different type of datas

4)

Identifiers are the names of variables ,functions ,classes etc.., defined by programmer.Identifiers are one of the primary requrements of every programming language.Every programming lanuage have their own rules in creation of identifirs
(as the rules of C)

In C program We have to declare every variable with apropriate data types .Data types are choosed according to the type of data is used to store in that variable

for example: int num;
char ch;