Is the illustration on Aliasing in C correct?

Question

I saw the link http://www.cs.uregina.ca/Links/class-info/cplusplus/Standards/Disk10/aliasing_c.html about aliasing in c. The program there is shown below.

/********************************
An example of aliasing in C.

Output:
3
3

********************************/

#include < stdio.h >

int main()

{

   int G_Var = 2;

   /* call SomeFunction with the Global Variable as a parameter */

   SomeFunction(G_Var); 

   return 0;
}

/* InputVar becomes an alias fo G_Var */

void SomeFunction(int &InputVar)
{

   int G_Var;
   int InputVar;

   /* Global Variable is set to new value */

   G_Var = InputVar + 1;       

   /* Equivalent to G_Var = G_Var + 1 */

   printf("%i\n", InputVar);

   printf("%i\n", G_Var);

}

Is the code correct and is working according to what is commented in the code?

Answer 1

Whoever wrote the link was severely incompetent and shouldn't be teaching C. They should rather enlist in a beginner's class themselves.

• int G_Var = 2; is not a global variable, it is a local one with automatic storage duration. Both the one in main() and the one inside the function.
• The code posted is C++, not C. C does not have references.
• The term alias/aliasing refers to when several pointers (or C++ references) may be assumed to point at the same memory location.
• int InputVar; in the function conflicts with the parameter name so the code doesn't make any sense. In case there were no name conflict, the variable would be uninitialized and then used, which would be senseless.

Is the code correct and is working according to what is commented in the code?

Whoever wrote this example was so confused that it's really hard to be telling what they are trying to teach, or in which language for that matter. The code does not compile for multiple fundamental reasons. Just forget about this mess.