This note is about arrays in programming and how they are stored in memory. It covers topics such as declaring and initializing arrays, accessing array elements, dynamic allocation of memory, and error handling. The video also mentions the use of arrays in Java and hints at upcoming topics like ins...
1.1 Arrays in Data Structure | Declaration, Initialization, Memory
representation
Jenny's Lectures CS IT
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;
to declare an integer variable. To declare an array, we would use:
int a[16];
This creates an array called "a" with 16 elements.
Initializing Arrays
Arrays can also be initialized with values. For example, we could
initialize an array of integers with the values 1, 2, and 3 like this:
int a[3] = {1, 2, 3};
Representing Arrays in Memory
To represent an array in memory, we need to know how the elements of the
array are stored. In a one-dimensional array, the elements are stored in
a single row with multiple columns.
Each element of the array takes up space in memory, depending on its data
type. For example, an array of integers would take up 2-4 bytes of memory
per element.
Overall, understanding memory and arrays is crucial to programming, as
they are fundamental building blocks of many programs and applications.
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