Compatibility Issue

If you replace the return statement in the function named doubleIt in Listing 5 with either of the following statements, the program will still compile and run successfully using Dev C++.  However, the compilation will fail using MS VS 6.0.

int y = x + x;
x + x;

This illustrates some of the compatibility issues that you can expect to encounter when working with C++.

The output

The screen output produced by the program is

a = 2
a doubled = 4