Arrays in C++

In the previous 4 posts (part 1, part 2, part 3, part 4) we covered the topic of Functions in C++. Today we'll jump onto the next topic and start with arrays.

Introduction:

We have already seen some of the commonly used data types of C++:

                            int, float, double, char 

Now, lets have a look at Composite Data Structures; 

Composite Data Structures:

In computer science, a composite data type is any data type which can be constructed in a program using the programming language's primitive data types and other composite types. So C++ has data structures for storing;

•Data items of same types

•Data items of different types

Arrays:

 Arrays are used to store related data items of the same type, Structures and Classes are used to store related data items of different types. We will study structures and classes later.

•          Arrays are used to store related data items of same type

•          Arrays are static entities, ie their size remains the same throughout program execution

•          An array is a: 

•          Consecutive group of memory locations

•          Same name and type (int, char, etc.)

•          To refer to an element of an array:

•          Specify array name and position number (index)

•          Format: arrayname[ position number ]

•          First element at will be always at position 0

•          N-element array c

int c[N]; //declaration

c[ 0 ], c[ 1 ] … c[ N - 1 ] are the array items

•          Nth element at position N-1

•Array elements are like other variables

–Assignment followed by printing for an integer array c

int c[1];

c[ 0 ] =  3;      // 0 is the Subscript here

cout << c[ 0 ];

•Can perform operations inside subscript

c[ 5 – 2 ] same as c[3]

Declaring Arrays:

•When declaring arrays, you have to specify; 

–Name

–Type of array ie any data type

–Number of elements/size

–type arrayName[ arraySize ];

int c[ 10 ];  // array of 10 integers

float d[ 3284 ]; // array of 3284 floats

•When it comes to declaring multiple arrays of same type

–Use comma separated list, like regular variables

int b[ 100 ], x[ 27 ];

Example Using Arrays:

•Arrays can be initialized using:

–a for loop

•Set each element

–An initializer list

•Specify each element when array declared

int n[ 5 ] = { 1, 2, 3, 4, 5 };

•If not enough initializers, rightmost elements 0

•If too many syntax errors

–If array size omitted, initializers determine size

int n[] = { 1, 2, 3, 4, 5 };

•5 initializers, therefore 5 element array