INTERVIEW QUESTIONS PROGRAMMING LANGUAGES C++ DETAILS

Question:
What are storage qualifiers in C++ ?

Answer: They are..
const
volatile
mutable
Const keyword indicates that memory once initialized, should not be altered by a program.
volatile keyword indicates that the value in the memory location can be altered even though
nothing in the program
code modifies the contents. for example if you have a pointer to hardware location that
contains the time, where hardware changes the value of this pointer variable and not the
program. The intent of this keyword to improve the optimization ability of the compiler.
mutable keyword indicates that particular member of a structure or class can be altered even
if a particular structure variable, class, or class member function is constant.
struct data
{
char name[80];
mutable double salary;
}
const data MyStruct = { "Satish Shetty", 1000 }; //initlized by complier
strcpy ( MyStruct.name, "Shilpa Shetty"); // compiler error
MyStruct.salaray = 2000 ; // complier is happy allowed
What is reference ??
reference is a name that acts as an alias, or alternative name, for a previously defined
variable or an object. prepending variable with "&" symbol makes it as reference. for
example:
int a;
int &b = a;
What is passing by reference?
Method of passing arguments to a function which takes parameter of type reference. for
example:
void swap( int & x, int & y )
{
int temp = x;
x = y;
y = x;
}
int a=2, b=3;
swap( a, b );
Basically, inside the function there won't be any copy of the arguments "x" and "y" instead
they refer to original variables a and b. so no extra memory needed to pass arguments and it
is more efficient.

They are..
const
volatile
mutable
Const keyword indicates that memory once initialized, should not be altered by a program.
volatile keyword indicates that the value in the memory location can be altered even though
nothing in the program
code modifies the contents. for example if you have a pointer to hardware location that
contains the time, where hardware changes the value of this pointer variable and not the
program. The intent of this keyword to improve the optimization ability of the compiler.
mutable keyword indicates that particular member of a structure or class can be altered even
if a particular structure variable, class, or class member function is constant.
struct data
{
char name[80];
mutable double salary;
}
const data MyStruct = { "Satish Shetty", 1000 }; //initlized by complier
strcpy ( MyStruct.name, "Shilpa Shetty"); // compiler error
MyStruct.salaray = 2000 ; // complier is happy allowed
What is reference ??
reference is a name that acts as an alias, or alternative name, for a previously defined
variable or an object. prepending variable with "&" symbol makes it as reference. for
example:
int a;
int &b = a;
What is passing by reference?
Method of passing arguments to a function which takes parameter of type reference. for
example:
void swap( int & x, int & y )
{
int temp = x;
x = y;
y = x;
}
int a=2, b=3;
swap( a, b );
Basically, inside the function there won't be any copy of the arguments "x" and "y" instead
they refer to original variables a and b. so no extra memory needed to pass arguments and it
is more efficient. Source: CoolInterview.com

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