Uninitialized variables

Hi everyone.
I'm new here, and I have a question, very simple for most of you... I guess.
Here's the code:

Code:

---

#include <iostream>
using namespace std;

int main ()
{
    int a, b, c;
    cout << a << endl << b << endl << c <<endl;
    system ("pause");
    return (0);
}

---

The result is:

2
16
2293672

How and why got the three variables those values??

Thank you.

Quote:

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Originally Posted by Rife

How and why got the three variables those values??

---

They happened to be the contents of the memory that those variables were allocated.

Thank you.
I presumed they should get value of 0.

So, the variables always should be initialiyed if we want to operate with them.

Quote:

---

Originally Posted by Rife

Thank you.
I presumed they should get value of 0.

So, the variables always should be initialiyed if we want to operate with them.

---

Yes, all local variables must be initialized. Local variables have whatever they happens to be in the memory they are given in the function [unless it's a debug build from V7.0+ of MS Visual studio, in which case uninitialized variables have a specific bit-pattern (e.g. 0xCC) filled into them to make it easier to detect uninitialized variables - but this is also not zero].

GLOBAL (and static) variables are initialized to zero.

--
Mats

As Matsp noted, in certain situations your variables will be initialized to 0 but it's considered very bad form and poor practice to expect your compiler to do the work you should be doing.

The long and short of it -- always initialize your variables.

Depends on what you consider the "work you should be doing". I personally like passing as much work as possible to the compiler.

In this case it's initializing variables/pointers/whatever. I generally take the approach "If I'm not initializing it myself expect bugs."