c++03

问题 I've been reading up on move semantics lately and how it was introduced into C++11. The main gist is that programs could become more efficient by creating objects by 'stealing' pointers to temporary objects. This is much more efficient than doing a deep copy of the temporary object to create new objects. In C++11 (and onward), this is achieved with the use of rvalue references. All temporary objects (objects that don't have a known place within your programs memory) are considered rvalues.

问题 I've been reading up on move semantics lately and how it was introduced into C++11. The main gist is that programs could become more efficient by creating objects by 'stealing' pointers to temporary objects. This is much more efficient than doing a deep copy of the temporary object to create new objects. In C++11 (and onward), this is achieved with the use of rvalue references. All temporary objects (objects that don't have a known place within your programs memory) are considered rvalues.

问题 I've been reading up on move semantics lately and how it was introduced into C++11. The main gist is that programs could become more efficient by creating objects by 'stealing' pointers to temporary objects. This is much more efficient than doing a deep copy of the temporary object to create new objects. In C++11 (and onward), this is achieved with the use of rvalue references. All temporary objects (objects that don't have a known place within your programs memory) are considered rvalues.

问题 I read here from the accepted answer that a std::deque has the following characteristic 1- Random access - constant O(1) 2- Insertion or removal of elements at the end or beginning - amortized constant O(1) 3- Insertion or removal of elements - linear O(n) My question is about point 2. How can a deque have an amortized constant insertion at the end or beginning? I understand that a std::vector has an amortized constant time complexity for insertions at the end. This is because a vector is

问题 I want to iterate through a STL set to do operations on elements pairwise in the set. For eg. if set S={1,2,3), I need to be able to check {1,2},{2,3},{1,3}. So a very wrong C++ code for this would be as follows- set<bitset<2501> > arr; unsigned sz = arr.size(); rep(i,sz-1) { for(j=i+1;j<sz;j++) { //do processing and in my case is an OR operation if(((arr[i])|(arr[j])) == num) { cnt++; } } } I wrote the above wrong code to give you a better idea of what I want to do. A better version (should

问题 I'm bound to C++03 and I have a non-copyable object (e.g. holding a resource). I need to use move-and-swap semantics to be able to do something similar and avoid copies: MyClass returnMyClass(void) { MyClass temp; // fill 'temp' members with actual data return temp; } int main(void) { MyClass test; test = returnMyClass(); // need to avoid copies } Is it possible to respect all these requirements in C++03? It is basically the same case of this, but for C++03. To put the question in other words

来源： https://stackoverflow.com/questions/57704539/default-constructor-of-the-structure-for-correct-stdmap-behaviour

问题 sprintf_s is a Microsoft implementation of the function sprintf where they patched a flaw, adding an argument to take a boundary value where the function is limited to write. An equivalent was introduced in C++11 : snprintf . But here, we are talking of C++03 syntax. Signatures: count_char_written sprintf(char* string_out, const char* output_template, VARIADIC_ARGS); // and count_char_written sprintf_s(char* string_out, size_t buffer_max_size, const char* output_template, VARIADIC_ARGS);

问题 Is there any guarantee that static class members are initialized before main is called? 回答1: I think no : [C++03: 3.6.2/3]: It is implementation-defined whether or not the dynamic initialization (8.5, 9.4, 12.1, 12.6.1) of an object of namespace scope is done before the first statement of main . If the initialization is deferred to some point in time after the first statement of main , it shall occur before the first use of any function or object defined in the same translation unit as the

问题 Is there any guarantee that static class members are initialized before main is called? 回答1: I think no : [C++03: 3.6.2/3]: It is implementation-defined whether or not the dynamic initialization (8.5, 9.4, 12.1, 12.6.1) of an object of namespace scope is done before the first statement of main . If the initialization is deferred to some point in time after the first statement of main , it shall occur before the first use of any function or object defined in the same translation unit as the