Take a look at the code below which takes two integers and returns the *address* of the memory location that holds their *sum*:

#include <iostream>
using namespace std;

int* foo(int a,int b)
{
  int sum = a + b;

  return &sum;
}

int main() {
  int* addr = foo(5, 6);
}

Executing the code above gives the following error at `main.cpp:6:7` :

```C++

  address of local variable 'sum' returned [-Wreturn-local-addr]. 

```

The compiler is not letting the function return the address (using the `&` operator) of the `sum` because `sum` was declared and initialized inside the function block, thus making it a *local* variable.

The `return` statement should *not* return a pointer that has the address of a local variable (`sum`) because, as soon as the function exits, *all local variables are destroyed* and your pointer will be pointing to someplace in the memory that you no longer own.

> If a pointer is referring to an object that is destroyed, the pointer is said to be a **dangling pointer** until it is given a new value.

Any use of a pointer with such a value is invalid. It is dangerous to have a dangling pointer like that as pointers or references to local variables are not allowed to escape the function where local variables live; hence, the compiler throws an error.

# Solution

Since the problem is that the return address is actually of a local variable, the solution would be to *dynamically allocate memory to a variable to hold the address and pass it to the function as a parameter*. Now, the variable is declared outside the function block and is no longer a local variable.

See the code below:

#include <iostream>
using namespace std;

int* foo(int a, int b, int* sum)
{
  *sum = a + b;
  return sum;
}

int main() {
  int *sum = new int;
  sum = foo(5,6,sum);

  cout << "The sum " << *sum << " is stored at address " << sum << endl;
}

The pointer to the `sum` is now declared in the `main` function and is passed to `foo` as a parameter; it is no longer a local variable inside the function block and, ​hence, the compiler has no problem with the return value being the memory location of `sum`.

Resolving the "function returns address of local variable" error

Take a look at the code below which takes two integers and returns the address of the memory location that holds their sum: 