Re: strange problem with OOP

"Alf P. Steinbach" <>
Sat, 24 Feb 2007 09:49:02 +0100
* openbysource:

I wrote this program:

#include <iostream>
using namespace std;
class sample
                int age;
                float salary;
                char status;
int main()
        sample s1;
        cout << "sizeof int = " << sizeof(int) << endl;
        cout << "sizeof float = " << sizeof(float) << endl;
        cout << "sizeof char = " << sizeof(char) << endl;
        cout << "sizeof sample class = " << sizeof(sample) << endl;
        cout << "sizeof sample class object = " << sizeof(s1) << endl;
        return 0;

Got this strange output:

sizeof int = 4
sizeof float = 4
sizeof char = 1
sizeof sample class = 12
sizeof sample class object = 12

Isn't it strange. I am using GCC 4.1.1. Isn't it should be 9 for the
last two one.

The compiler pads the struct with three extra bytes to make it a
multiple of four bytes large.

Depending on the machine and OS, this might improve the speed of
accessing such structs in an array, or it may be necessary to access
them at all.

With most compilers you can configure this.

A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
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