C++ C++;缩进输出类继承流
所以我想写一个缩进输出类,可以这样使用:C++ C++;缩进输出类继承流,c++,c++11,std,ofstream,manipulators,C++,C++11,Std,Ofstream,Manipulators,所以我想写一个缩进输出类,可以这样使用: Debug f; f.open("test.txt"); f << Debug::IndS << "Start" << std::endl; f << Debug::Ind << "test" << std::endl; f << Debug::IndE << "End" << std::endl; 所以Ind将打印当前缩进和递增缩进,Ind将打
Debug f;
f.open("test.txt");
f << Debug::IndS << "Start" << std::endl;
f << Debug::Ind << "test" << std::endl;
f << Debug::IndE << "End" << std::endl;
所以Ind将打印当前缩进和递增缩进,Ind将打印当前缩进,Ind将递减缩进并打印当前缩进。我尝试过这样创建它:
class Debug : public std::ofstream {
public:
Debug();
~Debug();
private:
std::string IndentText;
int _Indent;
public:
void SetIndentText(const char* Text);
inline void Indent(int Amount);
inline void SetIndent(int Amount);
inline std::ofstream& Ind (std::ofstream& ofs);
inline std::ofstream& IndS(std::ofstream& ofs);
inline std::ofstream& IndE(std::ofstream& ofs);
};
Debug::Debug () : std::ofstream() {
IndentText = " ";
}
Debug::~Debug () {
}
void Debug::SetIndentText (const char* Text) {
IndentText = Text;
}
void Debug::Indent (int Amount) {
_Indent += Amount;
}
void Debug::SetIndent(int Amount) {
_Indent = Amount;
}
std::ofstream& Debug::Ind (std::ofstream& ofs) {
for (int i = 0;i < _Indent;i++) {
ofs << IndentText;
}
return ofs;
}
std::ofstream& Debug::IndS (std::ofstream& ofs) {
ofs << Ind;
_Indent++;
return ofs;
}
std::ofstream& Debug::IndE (std::ofstream& ofs) {
_Indent--;
ofs << Ind;
return ofs;
}
类调试:公共std::of流{
公众:
调试();
~Debug();
私人:
std::字符串缩进文本;
整数缩进;
公众:
void SetIndentText(常量字符*文本);
内联无效缩进(整数金额);
内联void SetIndent(整数金额);
在线标准:ofstream&Ind(标准:ofstream&ofs);
在线标准:ofstream&IndS(标准:ofstream&ofs);
在线标准:ofstream&IndE(标准:ofstream&ofs);
};
Debug::Debug():std::ofstream(){
缩进文本=”;
}
调试::~Debug(){
}
void Debug::SetIndentText(常量字符*Text){
缩进文本=文本;
}
无效调试::缩进(整数金额){
_缩进+=金额;
}
void Debug::SetIndent(整数金额){
_缩进=金额;
}
std::ofstream&Debug::Ind(std::ofstream&ofs){
对于(int i=0;i<\u缩进;i++){
ofs您通常不应该继承
std::ostream
或类似于std::ofstream
的它的实现。请将它们包装到另一个类中
下面是我在评论中提到的想法的简短概述
#include <iostream>
#include <fstream>
using namespace std;
class Logger {
public:
Logger(ostream& os) : os_(os), curIndentLevel_(0) {}
void increaseLevel() { ++curIndentLevel_; }
void decreaseLevel() { --curIndentLevel_; }
private:
template<typename T> friend ostream& operator<<(Logger&, T);
ostream& os_;
int curIndentLevel_;
};
template<typename T>
ostream& operator<<(Logger& log, T op) {
for(int i = 0; i < log.curIndentLevel_ * 4; ++i) {
log.os_ << ' ';
}
log.os_ << op;
return log.os_;
}
int main() {
Logger log(cout);
log.increaseLevel();
log << "Hello World!" << endl;
log.decreaseLevel();
log << "Hello World!" << endl;
return 0;
}
这里有一个小变体,展示了如何使用
操作符简化编码。您通常不应该继承std::ostream
或它的实现,如std::ofstream
。将它们包装到另一个类中
下面是我在评论中提到的想法的简短概述
#include <iostream>
#include <fstream>
using namespace std;
class Logger {
public:
Logger(ostream& os) : os_(os), curIndentLevel_(0) {}
void increaseLevel() { ++curIndentLevel_; }
void decreaseLevel() { --curIndentLevel_; }
private:
template<typename T> friend ostream& operator<<(Logger&, T);
ostream& os_;
int curIndentLevel_;
};
template<typename T>
ostream& operator<<(Logger& log, T op) {
for(int i = 0; i < log.curIndentLevel_ * 4; ++i) {
log.os_ << ' ';
}
log.os_ << op;
return log.os_;
}
int main() {
Logger log(cout);
log.increaseLevel();
log << "Hello World!" << endl;
log.decreaseLevel();
log << "Hello World!" << endl;
return 0;
}
下面是一个小变体,显示如何使用操作符替代解决方案缩短编码:
#include <iostream>
#include <fstream>
class IndentClass {
public:
IndentClass();
~IndentClass();
private:
std::string IndentText;
int _Indent;
public:
inline void SetIndentText(const char* Text);
inline void Indent(int Amount);
inline void SetIndent(int Amount);
inline void ind (std::ostream& ofs);
class Ind_t {
public:
IndentClass& state;
Ind_t (IndentClass& _state) : state(_state) {}
friend inline std::ostream& operator<< (std::ostream& ofs, Ind_t& ind);
};
class IndS_t {
public:
IndentClass& state;
IndS_t (IndentClass& _state) : state(_state) {}
friend inline std::ostream& operator<< (std::ostream& ofs, IndS_t& ind);
};
class IndE_t {
public:
IndentClass& state;
IndE_t (IndentClass& _state) : state(_state) {}
friend inline std::ostream& operator<< (std::ostream& ofs, IndE_t& ind);
};
Ind_t Ind;
IndS_t IndS;
IndE_t IndE;
};
IndentClass::IndentClass () : IndentText(" "), _Indent(0), Ind(*this), IndS(*this), IndE(*this) {
}
IndentClass::~IndentClass () {
}
void IndentClass::SetIndentText (const char* Text) {
IndentText = Text;
}
void IndentClass::Indent (int Amount) {
_Indent += Amount;
}
void IndentClass::SetIndent(int Amount) {
_Indent = Amount;
}
void IndentClass::ind (std::ostream& ofs) {
for (int i = 0;i < _Indent;i++) {
ofs << IndentText;
}
}
std::ostream& operator<< (std::ostream& ofs, IndentClass::Ind_t& ind) {
ind.state.ind(ofs);
return ofs;
}
std::ostream& operator<< (std::ostream& ofs, IndentClass::IndS_t& inds) {
inds.state.ind(ofs);
inds.state.Indent(1);
return ofs;
}
std::ostream& operator<< (std::ostream& ofs, IndentClass::IndE_t& inde) {
inde.state.Indent(-1);
inde.state.ind(ofs);
return ofs;
}
int main () {
IndentClass i;
std::cout << i.IndS << "test" << std::endl;
std::cout << i.Ind << "test" << std::endl;
std::cout << i.IndE << "test" << std::endl;
return 0;
}
#包括
#包括
类缩进类{
公众:
缩进类();
~IndentClass();
私人:
std::字符串缩进文本;
整数缩进;
公众:
内联void SetIndentText(常量字符*文本);
内联无效缩进(整数金额);
内联void SetIndent(整数金额);
内联空隙索引(标准::ostream和ofs);
类别索引{
公众:
阶级与国家;
Ind_t(IndentClass&_state):state(_state){
friend inline std::ostream&operator替代解决方案:
#include <iostream>
#include <fstream>
class IndentClass {
public:
IndentClass();
~IndentClass();
private:
std::string IndentText;
int _Indent;
public:
inline void SetIndentText(const char* Text);
inline void Indent(int Amount);
inline void SetIndent(int Amount);
inline void ind (std::ostream& ofs);
class Ind_t {
public:
IndentClass& state;
Ind_t (IndentClass& _state) : state(_state) {}
friend inline std::ostream& operator<< (std::ostream& ofs, Ind_t& ind);
};
class IndS_t {
public:
IndentClass& state;
IndS_t (IndentClass& _state) : state(_state) {}
friend inline std::ostream& operator<< (std::ostream& ofs, IndS_t& ind);
};
class IndE_t {
public:
IndentClass& state;
IndE_t (IndentClass& _state) : state(_state) {}
friend inline std::ostream& operator<< (std::ostream& ofs, IndE_t& ind);
};
Ind_t Ind;
IndS_t IndS;
IndE_t IndE;
};
IndentClass::IndentClass () : IndentText(" "), _Indent(0), Ind(*this), IndS(*this), IndE(*this) {
}
IndentClass::~IndentClass () {
}
void IndentClass::SetIndentText (const char* Text) {
IndentText = Text;
}
void IndentClass::Indent (int Amount) {
_Indent += Amount;
}
void IndentClass::SetIndent(int Amount) {
_Indent = Amount;
}
void IndentClass::ind (std::ostream& ofs) {
for (int i = 0;i < _Indent;i++) {
ofs << IndentText;
}
}
std::ostream& operator<< (std::ostream& ofs, IndentClass::Ind_t& ind) {
ind.state.ind(ofs);
return ofs;
}
std::ostream& operator<< (std::ostream& ofs, IndentClass::IndS_t& inds) {
inds.state.ind(ofs);
inds.state.Indent(1);
return ofs;
}
std::ostream& operator<< (std::ostream& ofs, IndentClass::IndE_t& inde) {
inde.state.Indent(-1);
inde.state.ind(ofs);
return ofs;
}
int main () {
IndentClass i;
std::cout << i.IndS << "test" << std::endl;
std::cout << i.Ind << "test" << std::endl;
std::cout << i.IndE << "test" << std::endl;
return 0;
}
#包括
#包括
类缩进类{
公众:
缩进类();
~IndentClass();
私人:
std::字符串缩进文本;
整数缩进;
公众:
内联void SetIndentText(常量字符*文本);
内联无效缩进(整数金额);
内联void SetIndent(整数金额);
内联空隙索引(标准::ostream和ofs);
类别索引{
公众:
阶级与国家;
Ind_t(IndentClass&_state):state(_state){
friend inline std::ostream&Operator您不应该继承std::ofstream
,而是提供一个。我曾尝试提供操纵器的Ind
和IndE
,但这需要存储额外的信息,因此我认为创建一个特殊版本的ofstream会很有效。这是一个更干净的解决方案注意,应该使用任何流(cout
,stringstream
,fstream
)这里有一些关于如何编写I/O操纵器的更重要的链接:另外,对于重定向构造函数,使用类似于模板子(T..和&v):父(std::forward(v){}
您不应该继承std::ofstream
,而是提供一个。我尝试提供操纵器的Ind
IndS
和IndE
,但这需要存储额外的信息,因此我认为创建ofstream的特殊版本会很有效。这是一个更干净的解决方案,应该适用于任何stream(cout
,stringstream
,fstream
)这里有一些关于如何编写I/O操纵器的更重要的链接:另外,对于重定向构造函数,使用类似于模板子(T..和&v):父(std::forward(v){}
#include <iostream>
#include <fstream>
class IndentClass {
public:
IndentClass();
~IndentClass();
private:
std::string IndentText;
int _Indent;
public:
inline void SetIndentText(const char* Text);
inline void Indent(int Amount);
inline void SetIndent(int Amount);
inline void ind (std::ostream& ofs);
class Ind_t {
public:
IndentClass& state;
Ind_t (IndentClass& _state) : state(_state) {}
friend inline std::ostream& operator<< (std::ostream& ofs, Ind_t& ind);
};
class IndS_t {
public:
IndentClass& state;
IndS_t (IndentClass& _state) : state(_state) {}
friend inline std::ostream& operator<< (std::ostream& ofs, IndS_t& ind);
};
class IndE_t {
public:
IndentClass& state;
IndE_t (IndentClass& _state) : state(_state) {}
friend inline std::ostream& operator<< (std::ostream& ofs, IndE_t& ind);
};
Ind_t Ind;
IndS_t IndS;
IndE_t IndE;
};
IndentClass::IndentClass () : IndentText(" "), _Indent(0), Ind(*this), IndS(*this), IndE(*this) {
}
IndentClass::~IndentClass () {
}
void IndentClass::SetIndentText (const char* Text) {
IndentText = Text;
}
void IndentClass::Indent (int Amount) {
_Indent += Amount;
}
void IndentClass::SetIndent(int Amount) {
_Indent = Amount;
}
void IndentClass::ind (std::ostream& ofs) {
for (int i = 0;i < _Indent;i++) {
ofs << IndentText;
}
}
std::ostream& operator<< (std::ostream& ofs, IndentClass::Ind_t& ind) {
ind.state.ind(ofs);
return ofs;
}
std::ostream& operator<< (std::ostream& ofs, IndentClass::IndS_t& inds) {
inds.state.ind(ofs);
inds.state.Indent(1);
return ofs;
}
std::ostream& operator<< (std::ostream& ofs, IndentClass::IndE_t& inde) {
inde.state.Indent(-1);
inde.state.ind(ofs);
return ofs;
}
int main () {
IndentClass i;
std::cout << i.IndS << "test" << std::endl;
std::cout << i.Ind << "test" << std::endl;
std::cout << i.IndE << "test" << std::endl;
return 0;
}