Variables

Question 1

what are Variables?

Answer 1

A variable is nothing but a name given to a storage area that our programs can manipulate. Each variable in C has a specific type, which determines the size and layout of the variable’s memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable.

Question 2

char

Answer 2

Typically a single octet(one byte). It is an integer type.

Question 3

int

Answer 3

The most natural size of integer for the machine.

Question 4

float

Answer 4

A single-precision floating point value.

Question 5

double

Answer 5

A double-precision floating point value.

Question 6

void

Answer 6

Represents the absence of type.

Question 7

Variable Definition in C

Answer 7

A variable definition tells the compiler where and how much storage to create for the variable. A variable definition specifies a data type and contains a list of one or more variables of that type

Question 8

Variable Declaration in C

Answer 8

A variable declaration provides assurance to the compiler that there exists a variable with the given type and name so that the compiler can proceed for further compilation without requiring the complete detail about the variable. A variable definition has its meaning at the time of compilation only, the compiler needs actual variable definition at the time of linking the program.

A variable declaration is useful when you are using multiple files and you define your variable in one of the files which will be available at the time of linking of the program. You will use the keyword extern to declare a variable at any place. Though you can declare a variable multiple times in your C program, it can be defined only once in a file, a function, or a block of code.

Question 9

Lvalues and Rvalues in C

Lvalues

Answer 9

lvalue − Expressions that refer to a memory location are called “lvalue” expressions. An lvalue may appear as either the left-hand or right-hand side of an assignment.

Question 10

Lvalues and Rvalues in C

Rvalues

Answer 10

rvalue − The term rvalue refers to a data value that is stored at some address in memory. An rvalue is an expression that cannot have a value assigned to it which means an rvalue may appear on the right-hand side but not on the left-hand side of an assignment.