Long = 4 bytes

[Nobody/Anonymous]

hi when i'm compiling with dev cpp long is being allocated only 4 bytes isnt it supposed to allocate 8???

Im a newbie so please bear me....

[Nobody/Anonymous]

I did a quick check in my book, long is required to be at least 4 bytes, and at least as big as int.  It does not have to be bigger.

In some cases, you can use long long, though I don't remember if that works under gcc, I remember running into some display issues.

I also remember being smarter than I am too.

Wayne

[Nobody/Anonymous]

if you can ?, use a double if need be.
check your computer
#include <iostream>
     using namespace std;

int main( )
  {
  cout << sizeof(double) << endl;
     system("PAUSE");
    return 0;
  }

[Nobody/Anonymous]

I guess I was presuming that they wanted an integer type, which may have been a false presumption on my part...

Modifying the code you so graciously provided in the service of answering my question about long long:

#include <iostream>
using namespace std;

int main( )
{
cout << sizeof(double) << endl;
cout << sizeof(int) << endl;
cout << sizeof(long) << endl;
cout << sizeof(long long) << endl;
system("PAUSE");
return 0;
}

I find that long long does in fact show up as 8 bytes.   I still remember some funnies in getting it displayed or used.  He said, scratching his head...

Wayne

Wayne

[Nobody/Anonymous]

in my experience:

char=1=BYTE
int=2=WORD
long=4=DWORD
double=8

-yano

[Patrick Ogay]

ctypes: http://www.sysprog.net/ctype.html

A "word" is dependent on CPU-achitecture and compiler-implementation.
I read in R. Stevens "Network Programming" about some reliable length of datatypes: it's not so evident that an int is 16 or 32 bit.
(I think a short is 16, a long is 32 and a int is machine depended...)

Many libraries (particularly network) provide datatyes like int32,  to be certain about the length. 
Patrick

[Anonymous]

In a 32bit environment/compiler, long is normally 32bits (however it need not be so, simply at least 32bits, and at least as large as int - ANSI C specification).

You can use sizeof() to portably deternine the size of any type, class, struct, array, or instance of any of these.

Also <limits> (or <limits.h> in C) defines macros specifying the min and max values that may be represented by the basic types.

gcc does support long long (at least it does in the ARM cross-compiler version I also use). However, using long long may affect portability.