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F.21: fix variable name in example and text (#1981)

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saimen
2022-10-07 23:27:57 +02:00
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parent 65aae3ede6
commit 8181873753
1 changed files with 7 additions and 7 deletions
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CppCoreGuidelines.md
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@@ -3251,14 +3251,14 @@ In such cases, passing the object by reference [`T&`](#Rf-inout) is usually the
Explicitly passing an in-out parameter back out again as a return value is often not necessary. Explicitly passing an in-out parameter back out again as a return value is often not necessary.
For example: For example:
istream& operator>>(istream& is, string& s); // much like std::operator>>() istream& operator>>(istream& in, string& s); // much like std::operator>>()
for (string s; cin >> s; ) { for (string s; in >> s; ) {
// do something with line // do something with line
} }
Here, both `s` and `cin` are used as in-out parameters. Here, both `s` and `in` are used as in-out parameters.
We pass `cin` by (non-`const`) reference to be able to manipulate its state. We pass `in` by (non-`const`) reference to be able to manipulate its state.
We pass `s` to avoid repeated allocations. We pass `s` to avoid repeated allocations.
By reusing `s` (passed by reference), we allocate new memory only when we need to expand `s`'s capacity. By reusing `s` (passed by reference), we allocate new memory only when we need to expand `s`'s capacity.
This technique is sometimes called the "caller-allocated out" pattern and is particularly useful for types, This technique is sometimes called the "caller-allocated out" pattern and is particularly useful for types,
@@ -3266,11 +3266,11 @@ such as `string` and `vector`, that needs to do free store allocations.
To compare, if we passed out all values as return values, we would something like this: To compare, if we passed out all values as return values, we would something like this:
pair<istream&, string> get_string(istream& is) // not recommended pair<istream&, string> get_string(istream& in) // not recommended
{ {
string s; string s;
is >> s; in >> s;
return {is, move(s)}; return {in, move(s)};
} }
for (auto p = get_string(cin); p.first; ) { for (auto p = get_string(cin); p.first; ) {