Skip to main content

UNION

Definition:-
                Union is similar to structure, except it allows you to define the variable that share storage spaces.Defining a means creating a new data types.

How use union:-
                      when we create a structure by using struct keyword, now making a union we just replace the keyword struct with the keyword union , other syntax will be same.

Difference between Structure  and Union:- the only difference between them is in memory.
NOTE:- union is used for low level programming but structure mostly used for high level programming.

Program to access union:-
"""SHARE IT WITH YOUR FRIENDS IF HE DID NOT KNOW""""

Comments

Popular Posts

Static Memory Allocation

Statement are of two types:- Declaration:- in which we declare the variable Action:- in which for,if-else,getch,printf,scanf etc are used. SMA(STATIC MEMORY ALLOCATION):-                                whenever we create a program,there is a line of declaration statement(or data type declarartion statement) such as int a;char b;etc. Due to this statement we create a variable a,now this variable is the example of SMA.SMA means how much memory is consumed by variable at the time of compiler,this decision is taken before the compilation. At the compile time these variable such as a and b does not having a memory.Memory is given when program is run i.e when object file convert into .exe file.But when program is run how much memory is taken by the variable is decided at the compilation time.This is known as SMA(Static Memory Allocation).   

Compilation Process in C

Compilation The conversion of source code into object code is known as compilation.This process is done with the help of compiler. below is a full diagram of showing how source code convert into software(i.e software development in c) Explanation:- Source code :- the c programming coding is known as source code. save your programe with .c extension then your file become source file for example in fig: sum.c is a source file in which source code is written to print a hello. Prerocessor :- first we need a preprocessor software to convert source file (i.e .c file).Preprocessor handle all those statement which is starting from # symbol. Header file :-  In our programe as seen clearly in sum.c we did not create any header file (i.e which start from # symbol) we just use it.Preprocessor add the content of header file in our source file and creates a new file this file same as our source file but only difference is that the header file removed from the new file which ...

C PREPROCESSOR

DEF:- The C Preprocessor or cpp is the macro processor for the C and C++ programming language.It provide the ability for the inclusion of header file, macro expansion ,conditional compilation( #if,#ifdef,#ifndef,#else,#elif,#endif ) and line control. NOTE:- preprocessor directive are executed before compilation.All preprocessor directive starts with the # hash-symbol. There any many preprocessor directives in c language.In the figure there are two #if written. 1)#include:- The #include preprocessor directive is used to paste code of given file into current file. It is used include system-defined and user-defined header files. If included file is not found, compiler renders error. By the use of #include directive, we provide information to the preprocessor where to look for the header files. There are two variants to use #include directive. (a) #include <filename> :- The #include <filename> tells the compiler to look for the directory where system header file...