1/09/2015

C++ Arrays : Talks to you



# What is Array?
    # As you know that a variable can only store value one value at a time.
    # sometimes you want to create a lot of variable with the same type, So do you going to create each of them or Why do not you look at array? What if offers for you?
    # An Array is a series of elements of the same type placed in contiguous memory locations that can be easily accessed whenever wanted.

# Why Array was implemented ?
    # Instead of creating a lot of variables that will take more memory that will be better if we can declare an array in such a manner that can hold our all variables contents just using a single identifier name.


# How to declare an Array?
    # How to declare an Array using C++?
        # Let me declare an Array, so that i can put content there.
       
        type array_name[ array_size ];
       
        int foo[5];
       
        # We just declare an static array that can hold 5 integer values.

# How to declare and initialize an Array?
    # How to initialize Array using C++?
       
        int foo [5] = { 16, 2, 77, 40, 12071 };
        # Explicity initialize all elements of array
       
        int bar [5] = { 10, 11, 12};
        # remaining Array elements will be initialize to ZERO.
       
        int bar [5] = {};
        # all Array elements will be initialize to ZERO
       
        int foo[] = { 16, 7, 25, 40, 12909};
        # Compiler will assume that length of Array will be number of initialized elements.
       

        # New Syntax:- both are same
        int foo[] = { 10, 11, 12, 13, 14 };
        int foo[] { 10, 11, 12, 13, 14 };

# How to access values of an Array?
    # You need Index number of array element that you want to access.
    # Numbering starts from ZERO.
   
    int foo [3] = { 10, 11, 12};
   
    # means :-
    foo[0] = 10;
    foo[1] = 11;
    foo[2] = 12;

# What about Multidimensional Array?
    # Multidimensional Arrays are nothing more than Array of Arrays.
    # Means, an Array element will be an Array itself.
   
    int jimmy [3][5];
    # just declared a multidimensional array.
   
    [ 0x0 ] [ 0x1 ] [ 0x2 ] [ 0x3 ] [ 0x4 ]
    [ 1x0 ] [ 1x1 ] [ 1x2 ] [ 1x3 ] [ 1x4 ]
    [ 2x0 ] [ 2x1 ] [ 2x2 ] [ 2x3 ] [ 2x4 ]
   
    # Alternative Syntax for accessing Array elements:-
    ## Both are same:-
   
    int jimmy [3][5];
    int jimmy [15];    // 3 * 5 == 15


# What if i want to pass my Array as a function parameter?
    # To accept an array as parameter for a function, the parameters can be declared as the array type, but with empty array brackets, omitting the actual size of the array.

    int procedure ( int arg[] );
    # This function expects an Array of type Int.


    # You can call this function as
    int myarray[40];
    procedure( myarray );
   
   
# Is there any standard library to play with Array?
    # In C++ array are inherited from  C  language.
    # C++ has an alternative array type as a standard container. it is a type template ( a Class template) defined in header  <array>.
   
    # If you are using standard C++ array container then they give you some powerful methods that you can use with them.

 

# References :-
    http://www.cplusplus.com/doc/tutorial/arrays/
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