Define the term Scope, Visibility And Lifetime of a Variable

Category: Type And Variables

The scope of a variable is the range of program statements that can access that variable. The lifetime of a variable is the interval of time in which storage is bound to the variable. A variable is visible within its scope and invisible or hidden outside it.

 

Difference Between Declaring a Variable and Defining a Variable

Category: Type And Variables

Declaration of a variable in C hints the compiler about the type and size of the variable in compile time. Similarly, declaration of a function hints about type and size of function parameters. No space is reserved in memory for any variable in case of declaration.



 

Data Types along with Their Sizes and Ranges

Category: Type And Variables

Data Types : The type of a data object in C determines the range and kind of values an object can represent, the size of machine storage reserved for an object, and the operations allowed on an object. Functions also have types, and the function's return type and parameter types can be specified in the function's declaration.

 

What is a Storage class

Category: Type And Variables

A storage class specifies how the variables are used in the program.

 

What is Expressions ? Type of Expression

Category: Type And Variables

Arithmetic Expressions

 

An expression is a combination of variables constants and operators written according to the syntax of C language. In C every expression evaluates to a value i.e., every expression results in some value of a certain type that can be assigned to a variable. Some examples of C expressions are shown in the table given below.

 

What is a Variables? Declaration of Variables.

Category: Type And Variables

A variable is a value that can change any time. It is a memory location used to store a data value. A variable name should be carefully chosen by the programmer so that its use is reflected in a useful way in the entire program. Variable names are case sensitive. Example of variable names are



 

What is Constants? Type of constant

Category: Type And Variables

Constant value is the one which does not change during the execution of a program. C supports several types of constants.

 

What is scope & storage allocation of register, static and local variables

Category: Type And Variables

Register variables: belong to the register storage class and are stored in the CPU registers. The scope of the register variables is local to the block in which the variables are defined. The variables which are used for more number of times in a program are declared as register variables for faster access.



 

What is scope & storage allocation of extern and global variables

Category: Type And Variables

Extern variables: belong to the External storage class and are stored in the main memory. extern is used when we have to refer a function or variable that is implemented in other file in the same project. The scope of the extern variables is Global.



 

Where is an Auto Variables Stored

Category: Type And Variables

Main memory and CPU registers are the two memory locations where auto variables are stored. Auto variables are defined under automatic storage class. They are stored in main memory. Memory is allocated to an automatic variable when the block which contains it is called and it is de-allocated at the completion of its block execution.



 

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