About redeclaration of a variable

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I have declared a variable as int x and i compiled the program and when i delete this variable from the program and after compilation i again redeclare the same variable as int x, then will the address be same for this variable in the memory during redeclaration?and if the address changes ,why is it?

Posted 8-Aug-11 6:05am

Ashutosh_g

Updated 8-Aug-11 6:14am

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Fredrik Bornander 8-Aug-11 12:08pm

Is x a class or struct member, a global variable or a function local variable or a function argument variable?

Ashutosh_g 8-Aug-11 12:09pm

it is a local variable in main() function..

Richard MacCutchan 8-Aug-11 13:53pm

1. Maybe, it depends on the compiler.
2. Why does it matter?

YvesDaoust 9-Aug-11 2:33am

@TRK3: very well observed! But oooops, sorry, I deleted the Solution and your comment by accident and don't know how to undelete :(

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«_Superman_» · Answer 1 · 2011-08-08T06:39:00

Solution 2

A linker allocates addresses or offsets based on the order it finds it in the symbol table.
It has got nothing to do with the name of the variable.
So using the same name to re-declare a variable does not guarantee the same address that was previously allocated.

Posted 8-Aug-11 6:39am

«_Superman_»

Comments

John R. Shaw 8-Aug-11 23:41pm

5 - Good answer. If nothing else has changed, then it will probably be the same address. But, like you said, there is no guarantee.

mbue · Answer 2 · 2011-08-08T07:07:00

// Stack address: 0000100
for(int i=0;i<10;i++){ /*something */ } // Stack address: 00000FC

// Stack address: 0000100
// do anything else

for(int i=0;i<10;i++){ /*something */ } // Stack address: 00000FC

// Stack address: 0000100

You can see - the program reuses the same address on the stack.
Or in another way

void function(int x,int y)
{
  if(1==x)
  {
    int  a;
    // do...
  }
  if(1==y)
  {
    int  z; // <- 'z' uses the same adress as 'a' before
  }
}

Regards.