C++ Programming - References - Discussion
Discussion Forum : References - Programs (Q.No. 9)
9.
Which of the following statement is correct about the program given below?
#include<iostream.h>
int main()
{
int m = 2, n = 6;
int &x = m++;
int &y = n++;
m = x++;
x = m++;
n = y++;
y = n++;
cout<< m << " " << n;
return 0;
}Discussion:
5 comments Page 1 of 1.
Vivek Roy said:
5 years ago
A reference variable is same as constant pointer and arithmetic operation(i.e x++ & y++) is not allowed.
(1)
Rakesh said:
1 decade ago
Hi friends I am little bit confuse taking this program.
When I run this program in Turbo then output is 3, 7;
When I run in GCC compiler then it display an error;
"int &p = m++";
When I write it as like.
Int &p = ++m;
This it works properly.
My question is how can I guess, in which compiler we have to run this program if it is not mention in Question.
When I run this program in Turbo then output is 3, 7;
When I run in GCC compiler then it display an error;
"int &p = m++";
When I write it as like.
Int &p = ++m;
This it works properly.
My question is how can I guess, in which compiler we have to run this program if it is not mention in Question.
AnonymousAvenger said:
1 decade ago
Because References cannot be bound to temporary objects.
In "int &p = m++"
Compiler stores the old m value in a temporary object and then increment value of temporary object and returns the temporary object
However this statement will work:
int &p = ++m;
In "int &p = m++"
Compiler stores the old m value in a temporary object and then increment value of temporary object and returns the temporary object
However this statement will work:
int &p = ++m;
Avio said:
1 decade ago
C++03 3.10/1 says: "Every expression is either an lvalue or an rvalue." It's important to remember that lvalueness versus rvalueness is a property of expressions, not of objects.
Lvalues name objects that persist beyond a single expression. For example, obj , *ptr , ptr[index] , and ++x are all lvalues.
Rvalues are temporaries that evaporate at the end of the full-expression in which they live ("at the semicolon"). For example, 1729 , x + y , std::string("meow") , and x++ are all rvalues.
The address-of operator requires that its "operand shall be an lvalue". if we could take the address of one expression, the expression is an lvalue, otherwise it's an rvalue.
Lvalues name objects that persist beyond a single expression. For example, obj , *ptr , ptr[index] , and ++x are all lvalues.
Rvalues are temporaries that evaporate at the end of the full-expression in which they live ("at the semicolon"). For example, 1729 , x + y , std::string("meow") , and x++ are all rvalues.
The address-of operator requires that its "operand shall be an lvalue". if we could take the address of one expression, the expression is an lvalue, otherwise it's an rvalue.
Keshav Khetriwal said:
1 decade ago
Reference requires memory address not an ordinary integer value.
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