performance-inefficient-string-concatenation¶
This check warns about the performance overhead arising from concatenating
strings using the operator+, for instance:
std::string a("Foo"), b("Bar");
a = a + b;
Instead of this structure you should use operator+= or std::string’s
(std::basic_string) class member function append(). For instance:
std::string a("Foo"), b("Baz");
for (int i = 0; i < 20000; ++i) {
a = a + "Bar" + b;
}
Could be rewritten in a greatly more efficient way like:
std::string a("Foo"), b("Baz");
for (int i = 0; i < 20000; ++i) {
a.append("Bar").append(b);
}
And this can be rewritten too:
void f(const std::string&) {}
std::string a("Foo"), b("Baz");
void g() {
f(a + "Bar" + b);
}
In a slightly more efficient way like:
void f(const std::string&) {}
std::string a("Foo"), b("Baz");
void g() {
f(std::string(a).append("Bar").append(b));
}