Google's style guide about input/output parameters as pointers

Question

The Google C++ Style Guide draws a clear distinction (strictly followed by cpplint.py) between input parameters(→ const ref, value) and input-output or output parameters (→ non

Answer 1

The reason for demanding that output parameters are passed as pointers is simple:

It makes it clear at the call site that the argument is potentially going to be mutated:

foo(x, y);     // x and y won't be mutated
bar(x, &y);    // y may be mutated

When a code base evolves and undergoes incremental changes that are reviewed by people who may not know the entire context all the time, it is important to be able to understand the context and impact of a change as quickly as possible. So with this style rule, it is immediately clear whether a change introduces a mutation.