如果程序被指定像这样运行,那么在c++中解析命令行参数的最佳方式是什么:
prog [-abc] [input [output]]
是否有某种方法可以在标准库中实现这一点,或者我需要自己编写代码?
相关:
在unicode c++应用程序中解析命令行参数
如果程序被指定像这样运行,那么在c++中解析命令行参数的最佳方式是什么:
prog [-abc] [input [output]]
是否有某种方法可以在标准库中实现这一点,或者我需要自己编写代码?
相关:
在unicode c++应用程序中解析命令行参数
当前回答
我认为GNU GetOpt并不是马上就可以使用的。
Qt和Boost可能是一种解决方案,但您需要下载并编译大量代码。
所以我自己实现了一个解析器,它产生一个std::map<std::string, std::string>的参数。
例如,调用:
./myProgram -v -p 1234
地图将是:
["-v"][""]
["-p"]["1234"]
用法是:
int main(int argc, char *argv[]) {
MainOptions mo(argc, argv);
MainOptions::Option* opt = mo.getParamFromKey("-p");
const string type = opt ? (*opt).second : "";
cout << type << endl; /* Prints 1234 */
/* Your check code */
}
MainOptions.h
#ifndef MAINOPTIONS_H_
#define MAINOPTIONS_H_
#include <map>
#include <string>
class MainOptions {
public:
typedef std::pair<std::string, std::string> Option;
MainOptions(int argc, char *argv[]);
virtual ~MainOptions();
std::string getAppName() const;
bool hasKey(const std::string&) const;
Option* getParamFromKey(const std::string&) const;
void printOptions() const;
private:
typedef std::map<std::string, std::string> Options;
void parse();
const char* const *begin() const;
const char* const *end() const;
const char* const *last() const;
Options options_;
int argc_;
char** argv_;
std::string appName_;
};
MainOptions.cpp
#include "MainOptions.h"
#include <iostream>
using namespace std;
MainOptions::MainOptions(int argc, char* argv[]) :
argc_(argc),
argv_(argv) {
appName_ = argv_[0];
this->parse();
}
MainOptions::~MainOptions() {
}
std::string MainOptions::getAppName() const {
return appName_;
}
void MainOptions::parse() {
typedef pair<string, string> Option;
Option* option = new pair<string, string>();
for (const char* const * i = this->begin() + 1; i != this->end(); i++) {
const string p = *i;
if (option->first == "" && p[0] == '-') {
option->first = p;
if (i == this->last()) {
options_.insert(Option(option->first, option->second));
}
continue;
} else if (option->first != "" && p[0] == '-') {
option->second = "null"; /* or leave empty? */
options_.insert(Option(option->first, option->second));
option->first = p;
option->second = "";
if (i == this->last()) {
options_.insert(Option(option->first, option->second));
}
continue;
} else if (option->first != "") {
option->second = p;
options_.insert(Option(option->first, option->second));
option->first = "";
option->second = "";
continue;
}
}
}
void MainOptions::printOptions() const {
std::map<std::string, std::string>::const_iterator m = options_.begin();
int i = 0;
if (options_.empty()) {
cout << "No parameters\n";
}
for (; m != options_.end(); m++, ++i) {
cout << "Parameter [" << i << "] [" << (*m).first << " " << (*m).second
<< "]\n";
}
}
const char* const *MainOptions::begin() const {
return argv_;
}
const char* const *MainOptions::end() const {
return argv_ + argc_;
}
const char* const *MainOptions::last() const {
return argv_ + argc_ - 1;
}
bool MainOptions::hasKey(const std::string& key) const {
return options_.find(key) != options_.end();
}
MainOptions::Option* MainOptions::getParamFromKey(
const std::string& key) const {
const Options::const_iterator i = options_.find(key);
MainOptions::Option* o = 0;
if (i != options_.end()) {
o = new MainOptions::Option((*i).first, (*i).second);
}
return o;
}
其他回答
提振。Program_options
我在一些项目中使用过GetPot: http://getpot.sourceforge.net/
主要特点:所有东西都在一个头文件中,没有构建的麻烦。只需将它保存在你机器上的某个地方,并在你的文件中使用main()
最近没有更新,但它有很好的文档记录,工作得很好。
如果你只想自己处理命令行选项,最简单的方法是:
vector<string> args(argv + 1, argv + argc);
在main()的顶部。这将把所有命令行参数复制到std::strings的向量中。然后,您可以使用==轻松地比较字符串,而不是无休止的strcmp()调用。例如:
int main(int argc, char **argv) {
vector<string> args(argv + 1, argv + argc);
string infname, outfname;
// Loop over command-line args
// (Actually I usually use an ordinary integer loop variable and compare
// args[i] instead of *i -- don't tell anyone! ;)
for (auto i = args.begin(); i != args.end(); ++i) {
if (*i == "-h" || *i == "--help") {
cout << "Syntax: foomatic -i <infile> -o <outfile>" << endl;
return 0;
} else if (*i == "-i") {
infname = *++i;
} else if (*i == "-o") {
outfname = *++i;
}
}
}
[编辑:我意识到我正在复制argv[0],程序的名称,到args -已修复。]
我可以建议使用模板化的c++命令行解析器库(GitHub上的一些分支是可用的),API非常直接并且(引用自网站):
该库完全在头文件中实现,因此很容易 与其他软件一起使用和分发。它是MIT授权的 无后顾之忧的发行许可证。
这是手册中的一个例子,为了简单起见,这里有颜色:
#include <string>
#include <iostream>
#include <algorithm>
#include <tclap/CmdLine.h>
int main(int argc, char** argv)
{
// Wrap everything in a try block. Do this every time,
// because exceptions will be thrown for problems.
try {
// Define the command line object, and insert a message
// that describes the program. The "Command description message"
// is printed last in the help text. The second argument is the
// delimiter (usually space) and the last one is the version number.
// The CmdLine object parses the argv array based on the Arg objects
// that it contains.
TCLAP::CmdLine cmd("Command description message", ' ', "0.9");
// Define a value argument and add it to the command line.
// A value arg defines a flag and a type of value that it expects,
// such as "-n Bishop".
TCLAP::ValueArg<std::string> nameArg("n","name","Name to print",true,"homer","string");
// Add the argument nameArg to the CmdLine object. The CmdLine object
// uses this Arg to parse the command line.
cmd.add( nameArg );
// Define a switch and add it to the command line.
// A switch arg is a boolean argument and only defines a flag that
// indicates true or false. In this example the SwitchArg adds itself
// to the CmdLine object as part of the constructor. This eliminates
// the need to call the cmd.add() method. All args have support in
// their constructors to add themselves directly to the CmdLine object.
// It doesn't matter which idiom you choose, they accomplish the same thing.
TCLAP::SwitchArg reverseSwitch("r","reverse","Print name backwards", cmd, false);
// Parse the argv array.
cmd.parse( argc, argv );
// Get the value parsed by each arg.
std::string name = nameArg.getValue();
bool reverseName = reverseSwitch.getValue();
// Do what you intend.
if ( reverseName )
{
std::reverse(name.begin(),name.end());
std::cout << "My name (spelled backwards) is: " << name << std::endl;
}
else
std::cout << "My name is: " << name << std::endl;
} catch (TCLAP::ArgException &e) // catch any exceptions
{ std::cerr << "error: " << e.error() << " for arg " << e.argId() << std::endl; }
}
GNU顶。
一个使用GetOpt的简单示例:
// C/C++ Libraries:
#include <string>
#include <iostream>
#include <unistd.h>
// Namespaces:
using namespace std;
int main(int argc, char** argv) {
int opt;
bool flagA = false;
bool flagB = false;
// Shut GetOpt error messages down (return '?'):
opterr = 0;
// Retrieve the options:
while ( (opt = getopt(argc, argv, "ab")) != -1 ) { // for each option...
switch ( opt ) {
case 'a':
flagA = true;
break;
case 'b':
flagB = true;
break;
case '?': // unknown option...
cerr << "Unknown option: '" << char(optopt) << "'!" << endl;
break;
}
}
// Debug:
cout << "flagA = " << flagA << endl;
cout << "flagB = " << flagB << endl;
return 0;
}
如果有接受参数的选项,也可以使用optarg。