memory allocation for auto variables in a loop

[dwjang]

Hi,

I have the following simple program which prints out the address of a local variable inside loop. I assume the address of that variable changes by iteration, but it was not. Could someone explain me why?

#include <iostream>

int main() {

for(int i=0; i<5; i++) {
float p = 3.14;
std::cout << "addr of p : " << &p << std::endl;
}

return 0;
}

result:
addr of p : 0x7fffda254c88
addr of p : 0x7fffda254c88
addr of p : 0x7fffda254c88
addr of p : 0x7fffda254c88
addr of p : 0x7fffda254c88

Thanks,
DW

[Athar]

The local variable is destroyed after each iteration, so it suggests itself to reuse the same address for the next one.

Why do you think it should change?

[dwjang]

Hi,

I thought it is not necessarilly be same all the time. So for example, if I run this on thread, it should be different, shouldn't it?

Thanks,

[Athar]

I thought it is not necessarilly be same all the time.

No one says it has to be, that's up to the compiler.

So for example, if I run this on thread, it should be different, shouldn't it?

But you're running this in only one thread.