Scope and return values in C++

Question

I am starting again with c++ and was thinking about the scope of variables. If I have a variable inside a function and then I return that variable will the variable not be \

Answer 1

It really depends on what kind of variable you are returning. If you return a primitive then it is returned by copy, not by reference so the value is copied to the top of the stack (or, more often placed into a register) where the calling function can get it. If you allocate an object or memory on the heap and return a pointer then it doesn't die because it's on the heap, not the stack. If you allocate something on the stack, however, and return it, that would be a bad thing. For instance, either of these would be very bad:

int *myBadAddingFunction(int a, int b)
{
    int result;

    result = a + b;
    return &result; // this is very bad and the result is undefined
}

char *myOtherBadFunction()
{
    char myString[256];

    strcpy(myString, "This is my string!");
    return myString; // also allocated on the stack, also bad
}