地址算术 [英] Address Arithmetic
问题描述
大家好，
如果我使用G ++ 4.0.2编译以下程序并运行它，我会得到
以下输出：
#include< iostream>
使用命名空间std;
int main（char argc，char * argv []） {
int x，y;
cout<< 地址x = << （无符号长）& x<< endl;
cout<< y =的地址。 << （无符号长）& y<< endl;
cout<< 地址差异="
<< （无符号长）& y - （无符号长）& x<<结束;
返回1;
}
$ ./a.out
地址x = 3219613408
地址y = 3219613404
地址差异= 4294967292
我想知道为什么地址差异显示一个长的，看似
的随机数，而不是4？我错了吗？
谢谢，
-Andy
Hi all,
If I compile the following program with G++ 4.0.2 and run it I get the
following output:
#include <iostream>
using namespace std;
int main(char argc, char *argv[]) {
int x, y;
cout << "Address of x = " << (unsigned long)&x << endl;
cout << "Address of y = " << (unsigned long)&y << endl;
cout << "Difference in addresses = "
<< (unsigned long)&y - (unsigned long)&x << endl;
return 1;
}
$ ./a.out
Address of x = 3219613408
Address of y = 3219613404
Difference in addresses = 4294967292
I''m wondering why does "Difference in addresses" show a long, seemingly
random, number instead of 4? Am I casting things wrong?
Thanks,
-Andy
推荐答案
./ a.out
地址x = 3219613408
地址y = 3219613404
地址差异= 4294967292
我想知道为什么地址差异显示一个长的，看似
的随机数，而不是4？我错了吗？
谢谢，
-Andy
./a.out
Address of x = 3219613408
Address of y = 3219613404
Difference in addresses = 4294967292
I''m wondering why does "Difference in addresses" show a long, seemingly
random, number instead of 4? Am I casting things wrong?
Thanks,
-Andy
Acck ！在提交之前我应该更长时间地回顾一下我的问题
UseNet :-(。由于某种原因，y在地址
空间中的x之前分配。对无符号值进行算术运算产生下溢和大
值。
没关系。
-Andy
aist ... @ gmail.com写道：
Acck! I should review my problems longer before submitting them to
UseNet :-(. For some reason y is allocated before x in the address
space. Doing arithmatic on the unsigned values underflows and a "big"
value is produced.
Never mind.
-Andy
aist...@gmail.com wrote:
大家好，
如果我编译以下程序使用G ++ 4.0.2并运行它我得到
以下输出：
#include< iostream>
使用命名空间std;
int main（char argc，char * argv []）{
int x，y;
cout<<""地址x ="<<（unsigned long）& x<< endl;
cout<<""地址y ="<<（unsigned long）& y<< endl;
cout<<""地址差异="
<<（unsigned lo ng）& y - （无符号长）& x<<结束;
返回1;
}
Hi all,
If I compile the following program with G++ 4.0.2 and run it I get the
following output:
#include <iostream>
using namespace std;
int main(char argc, char *argv[]) {
int x, y;
cout << "Address of x = " << (unsigned long)&x << endl;
cout << "Address of y = " << (unsigned long)&y << endl;
cout << "Difference in addresses = "
<< (unsigned long)&y - (unsigned long)&x << endl;
return 1;
}
./ a.out
地址x = 3219613408
地址y = 3219613404
地址差异= 4294967292
我想知道为什么地址差异显示一个长的，看似
的随机数，而不是4？我错了吗？
谢谢，
-Andy
./a.out
Address of x = 3219613408
Address of y = 3219613404
Difference in addresses = 4294967292
I''m wondering why does "Difference in addresses" show a long, seemingly
random, number instead of 4? Am I casting things wrong?
Thanks,
-Andy
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