To allow you to single-step through a program with a debugger, you have to provide information to allow the debugger to associate machine code with source code. At the very least, this means switching off all optimizations, since in an attempt to optimize code the C++ compiler will rearrange code. Optimizations are switched off by default (so the using the /Od switch is redundant), but clearly, to be able to debug a process and single-step through C++ code you need to remove all the /O optimization switches.
Since the C++ Standard Library uses the C Runtime, you will need to compile your code to use the latter's debug builds. The switch you use depends on whether you are building a process or Dynamic Link Library ...
