Arrays in data structures notes

1.1 Arrays in Data Structure | Declaration, Initialization,
Memory representation


Understanding Memory and Arrays in Programming

In programming, memory is essentially a long tape of bytes, with each byte containing 8 bits.
This can be extended to both sides, making it open-ended. To understand the need for
arrays, we need to examine how areas can be declared, initialized, and represented in
memory.


Storing Values in Memory


To store a value in memory, we need to know how much space will be allocated for it. For
example, the data type int typically takes up 4 bytes to store an integer. The number 5 would
need to be converted to binary, which is 32 bits or 4 bytes. In traditional compilers, we
generally take 2 or 4 bytes to be the data type for storing numbers. So, if we were storing an
integer, it would take up 2-4 bytes in memory.


The memory manager would allocate some memory for storing a variable, and the value
stored in memory would be represented in binary. For example, the value stored in a variable
could be 5, which would be represented as 101 in binary.


Using Arrays


An array is a collection of more than one element of the same datatype. For example, an
array of characters would be of the data type char, and an array of integers would be of the
data type int. The number of elements in an array is determined by the size of the array.


To declare an array in programming, we use a specific syntax. In C language, for example, we
would write:


int n;