R
Raj
Hi friends....
Could any one tell me atleast one application of anonymous uniouns in
C++?
Thank you
Could any one tell me atleast one application of anonymous uniouns in
C++?
Thank you
L
Luke Meyers
Raj said:
Keeping interns busy.
Luke
J
James Aguilar
Homework questions that people on a newsgroup would rather not answer
for you?
for you?
Z
Zara
Transmogrifying normal unions into state-of-the-art maintainer traps
T
Tom
Very interesting. I've never even heard of them before.
http://windowssdk.msdn.microsoft.co...html/36da2365-06a0-4e22-9665-e89eb28358ad.asp
So ... I played around with them a bit and modified the above example
program (see below). Note how the printed out value of x changes.
Demonstrating that the union's variables are sharing the same memory
space. My C++ I/O skills are still lacking -- so I used my good ol'
friend printf().
What good is it? It allows a list of variables of varying type to
share the memory space of the longest type. Thus conserving memory
resources. Now, let's make everyone cringe. Just buy a gig of ram and
declare a bunch of global variables and don't worry about conserving
memory.
)// anonymous_unions.cpp
// compile with: /EHsc
#include <iostream>
#include <stdio.h>
using namespace std;
int main() {
union {
int d;
char *f;
double x;
};
f = "test";
x = 999999999999.999;
printf("x = %18.3f\n", x);
d = INT_MAX;
cout << "INT_MAX = " << d << endl;
printf("x = %18.3f\n", x);
f = "here's a really long string stored in stack memory and not
allocated until run time; however, the pointer address resides in the
anonymous union";
cout << f << endl;
cout << " sizeof(int): " << sizeof(int) << endl;
cout << "sizeof(double): " << sizeof(double) << endl;
cout << " sizeof(char*): " << sizeof(char*) << endl;
}
// Program Output
// x = 999999999999.999
// INT_MAX = 2147483647
// x = 999999930368.000
// here's a really long string stored in stack memory and not
allocated until run time; however, the pointer address resides in the
anonymous union
// sizeof(int): 4
// sizeof(double): 8
// sizeof(char*): 4
B
benben
Raj said:
Constructing (almost) variant data type (almost) without dynamic memory
allocation.
Ben