What is Array?
Introduction
The simplest form of array may be defined abstractly as a finite ordered set of homogeneous elements. By “finite” we mean that there is a specific number of elements in the array this number may be large or small, but it must exist. By “ordered” we mean that the elements of the array are arranged so that there is a zeroth, first, second, third, and so forth. By “homogeneous” we mean that all the elements in the array must be of the same type.
For example, an array may contain all integers or all characters but may not contain both.
| Fundamental Syntax <Data_type> <Array_name> [size]; Declaration of Array Int number [3]; char data[5]; |
| Initialization of array 1-way 2-way int number[3] = { 9, 5, 2 }; number[0] =9; number[1] =7; number[2] =5; char data[3]={‘a’,’b’,’c’}; |
| Types of Array Accordingly structure of memory arrays are two types 1st One Dimension Array and Multi Dimension Array. |
| Array how to organize in memory |
| Array index | Elements | Addresses |
| -LB- X[0] | 1 00000001 | 0x0000 |
| X[1] | 2 00000010 | 0x0001 |
| X[2] | 3 00000011 | 0x0002 |
| X[3] | 4 00000100 | 0x0003 |
| X[4] | 5 00000101 | 0x0004 |
| X[5] | 6 00000110 | 0x0005 |
| X[6] | 7 00000111 | 0x0006 |
| … … . … | . … … ….. | ………..… |
| X[127] | 127 01111111 | 0X000.. |
| Array index start from zero because memory addresses are start from zero. Total number of element can be present in array X[size] is depends on the size of the data type which is totally depends on compiler and operating system. The range of the value is depends on the type and size of variable. The size of memory address is also depends on the type and size of the elements. 1 Byte value range is 8 bit 28-1 address means -128 to 127 00000000 ->0 00000001 ->127 . 01111111 ->127 10000000 ->128 . -128 -> 11111111 total -> 255 . Basic problems on array . *Length of the array? *Finding address of particular array index. *What should be the time complexity? |