Exercise 9.34

Assuming vi is a container of ints that includes even and odd values, predict the behavior of the following loop. After you've analyzed this loop, write a program to test whether your expectations were correct.

iter = vi.begin();
while (iter != vi.end())
    if (*iter % 2)
        iter = vi.insert(iter, *iter);
    ++iter;

Solution

The program would run indefinitely upon reaching an odd value, replicating it again and again, because iter is only incremented once rather than twice. See 34.cc. Upon running 34, it is also worth noting the implied missing brace around the while loop does not change the effect of the program.