22

これらの2つのクラスの実装を調べていたところ、strstreamクラスが非推奨になっていることがわかりました。

また、クラスを置換として使用する場合、クラスオブジェクトはバッファのディープコピーを維持するstringstreamため、バッファへのログイン方法に大きな違いがあります。stringstream

クラスに置き換えstrstreamているときに誰かが問題に直面しましたか？stringstream

このコードの出力は何で、その理由は何ですか？

#include<iostream>
#include <sstream>
#include <strstream>



int main(){

    char strArr[] = "Soheb Khan is great";

    char stringArr[] = "TurboCharging";

    std::strstream strStream(strArr,19);

    std::stringstream stringStream(std::string(stringArr,19));

    std::cout<<"Before Modification strArr= "<<strArr<<" & stringArr= "<<stringArr<<std::endl;

    strStream << "Fifa 2012 is nice";


    stringStream << "Sometimes its sucks";


    std::cout<<"After Modification strArr= "<<strArr<<" & stringArr= "<<stringArr<<std::endl;

    return 0;


}
4

1 に答える 1

13

The classes from <strstream> are hideous to use. When they were more popular I haven't seen any correct production used (well, they got corrected when I spotted the problems). Either people didn't terminate the string using std::ends or they didn't release the memory using s.freeze(0) (or, most often, both). Although the <sstream> class do create a copy I haven't found this to be a problem.

In case memory allocation actually matters for your use case, either because you need to allocate large chunks or because you have many of them, you can take control easily and have data read from or written to buffers you provide using a custom stream buffer. For example, a stream buffer writing to a readily allocate chunk of memory is trivial to write:

struct omembuf
    : std::streambuf {
{
    omembuf(char* base, std::size_t size) {
        this->setp(base, base + size);
    }
    char* begin() const { return this->pbase(); }
    char* end() const { return this->pptr(); }
};
于 2012-12-15T15:04:38.300 に答える