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| Code Block |
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namespace MyNamespace {
int Ii;
}
namespace MyNamespace {
int Ji;
}
void f() {
MyNamespace::Ii = MyNamespace::Ji = 12;
} |
The standard library introduces the namespace std for standards-provided declarations such as std::string, std::vector, and std::for_each. However, it is undefined behavior to introduce new declarations in namespace std except under special circumstances. The C++ Standard, [namespace.std], paragraphs 1 and 2 [ISO/IEC 14882-2014], states:
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#include <functional>
#include <iostream>
#include <string>
class MyString {
std::string Datadata;
public:
MyString(const std::string &Datadata) : Datadata(Datadata) {}
const std::string &get_data() const { return Datadata; }
};
namespace std {
template <>
struct plus<string> : binary_function<string, MyString, string> {
string operator()(const string &LHSlhs, const MyString &RHSrhs) const {
return LHSlhs + RHSrhs.get_data();
}
};
}
void f() {
std::string S1s1("My String");
MyString S2s2(" + Your String");
std::plus<std::string> Pp;
std::cout << Pp(S1s1, S2s2) << std::endl;
}
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Compliant Solution
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|---|---|---|---|---|
| ||||
#include <iostream>
#include <string>
class MyString {
std::string Datadata;
public:
MyString(const std::string &Datadata) : Datadata(Datadata) {}
const std::string &get_data() const { return Datadata; }
};
struct my_plus : std::binary_function<std::string, MyString, std::string> {
std::string operator()(const std::string &LHSlhs, const MyString &RHSrhs) const {
return LHSlhs + RHSrhs.get_data();
}
};
void f() {
std::string S1s1("My String");
MyString S2s2(" + Your String");
my_plus Pp;
std::cout << Pp(S1s1, S2s2) << std::endl;
} |
Risk Assessment
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