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C Programming Basics

The document discusses keywords, identifiers, and data types in C programming. It defines keywords as reserved words that have special meaning. Identifiers are unique names given to variables and functions. Data types determine the type and size of variable data and include basic types like int, char, float, and double as well as derived types like arrays and structures.

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33 views4 pages

C Programming Basics

The document discusses keywords, identifiers, and data types in C programming. It defines keywords as reserved words that have special meaning. Identifiers are unique names given to variables and functions. Data types determine the type and size of variable data and include basic types like int, char, float, and double as well as derived types like arrays and structures.

Uploaded by

A.I Safin
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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C Keywords

Keywords are predefined, reserved words used in programming that have


special meanings to the compiler. Keywords are part of the syntax and they
cannot be used as an identifier. For example:

C Keywords

auto double int struct

break else long switch

case enum register typedef

char extern return union

continue for signed void

do if static while

default goto sizeof volatile

const float short unsigned

C Identifiers
Identifier refers to name given to entities such as variables, functions,
structures etc.

Identifiers must be unique. They are created to give a unique name to an


entity to identify it during the execution of the program. For example:

Int money;

Double accountbalance;
Rules for naming identifiers

1. A valid identifier can have letters (both uppercase and lowercase


letters), digits and underscores.

2. The first letter of an identifier should be either a letter or an


underscore.

3. You cannot use keywords like int , while etc. as identifiers.


4. There is no rule on how long an identifier can be. However, you may
run into problems in some compilers if the identifier is longer than 31
characters.

C Data Types
In C programming, data types are declarations for variables. This
determines the type and size of data associated with variables. For
example

Basic types
Here's a table containing commonly used types in C programming for quick
access.

Type Size (bytes) Format Specifier

int at least 2, usually 4 %d , %i

char 1 %c

float 4 %f

double 8 %lf

int

Integers are whole numbers that can have both zero, positive and negative
values but no decimal values. For example, 0 , -5 , 10
We can use int for declaring an integer variable.

float and double

float and double are used to hold real numbers.


char

Keyword char is used for declaring character type variables


short and long

If you need to use a large number, you can use a type specifier long

short and long

If you need to use a large number, you can use a type specifier long

Derived Data Types


Data types that are derived from fundamental data types are derived types.
For example: arrays, pointers, function types, structures, etc.

We will learn about these derived data types in later tutorials.

• bool type

• Enumerated type

• Complex types

C programme

#include <stdio.h>

int main() {

int num1, num2, sum;


printf("Enter two integers: ");

scanf("%d %d", &num1, &num2);

sum = num1 + num2;

printf("Sum of %d and %d is %d\n", num1, num2, sum);

return 0;

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