What is inner returns in c plus plus?

Answer 1

Inner returns is not part of standard terminology, so it's difficult to say exactly what it means. It sounds as though it means a return statement other than the one that would typically appear as the final statement in a function. For instance:

int foo(int x)

{

if(!x)

return(-1); // inner return?

return(x*x); // typical return?

}

Differentiating return statements in this way is somewhat meaningless. All we're really saying is that the function has multiple return paths, in this case 2 distinct return paths. A more complex function might have several return paths, some more deeply nested than others, but it makes no real difference, so long as every reachable path has a return statement. In some cases, a function may not have a final return statement at all, simply because the function is guaranteed to never reach that point, because all possible routes through the function lead to an "inner" return path. For example:

int foo(int x)

{

if(!x)

return(-1);

switch(x)

{

case(1): return(x);

case(2): return(x*x);

default: return(x*x*x);

}

}

In the above example, there is no return statement before the final closing brace, because the code is guaranteed never to reach that point. All the return paths are "inner" returns.

We could just as easily write the exact same function as follows:

int foo(int x)

{

switch(x)

{

case(0): return(-1);

case(1): return(x);

case(2): return(x*x);

defaut: return(x*x*x);

}

}

Or this way:

int foo(int x)

{

switch(x)

{

case(0): return(-1);

case(1): return(x);

case(2): return(x*x);

}

return(x*x*x);

}

The logic is the same in each case, it's just a question of which is easier to read and understand. Out of all three, the second is perhaps the simplest to understand because all the logic is contained within the switch statement. But as far as the compiler is concerned, there should be no difference. A good optimiser should compile all three with exactly the same assembly instructions.