Variables in C Programming

A variable in C is a type of container that can hold a particular type of value, and its type is defined by its data type.

For example: int x;

Here, x is a variable of integer type, so it can hold only one integer value at a time.

Memory is allocated for a variable when it is defined, and the size of the allocation depends on the compiler. Generally, 2 bytes are allocated for an integer variable. The value that was present in those 2 bytes before assigning a value to the variable is known as a garbage value.

In C, when you assign a value to a variable, you are actually copying the value to the memory location that the variable represents.

int a = 1;
int b = 2;
a = b; // This doesn't mean b is assigned to a.

Variables in C are memory locations that hold values. When you assign a value to a variable in C, you are actually copying the value to the memory location that the variable represents.

Basic terms related to variables

1. Definition

   • Allocates memory for a variable
   • For example, in int x; 2 bytes are allocated for x.

2. Declaration

   • Means providing information to the compiler about the data type of the variable.
   • For example, in int x;, the information is given to the compiler that the data type of x is int.

3. Initialization

   • Assigns an initial value to a variable at the time of declaration.
   • data_type variable_name = value;
   • For example, int x = 1;
   • Note:
     • Static initialization happens at compile time.
     • Dynamic initialization happens at runtime.

Define and Declare

Sign bit and range

• The first bit is known as the sign bit. It’s the most significant bit.
• 0 represents a positive value, and 1 represents a negative value.
• Range is determined by $2^{slots}-1$

C is an expanding language where byte allocation depends on the compiler. While bytes are cheap for us, C prioritizes accuracy and range at the cost of efficiency and memory.