Java有一个方便的分割方法:
String str = "The quick brown fox";
String[] results = str.split(" ");
在c++中有简单的方法来做到这一点吗?
Java有一个方便的分割方法:
String str = "The quick brown fox";
String[] results = str.split(" ");
在c++中有简单的方法来做到这一点吗?
当前回答
这是一个非常简单的问题:
#include <vector>
#include <string>
using namespace std;
vector<string> split(const char *str, char c = ' ')
{
vector<string> result;
do
{
const char *begin = str;
while(*str != c && *str)
str++;
result.push_back(string(begin, str));
} while (0 != *str++);
return result;
}
其他回答
下面是一个示例标记器类,它可以实现您想要的功能
//Header file
class Tokenizer
{
public:
static const std::string DELIMITERS;
Tokenizer(const std::string& str);
Tokenizer(const std::string& str, const std::string& delimiters);
bool NextToken();
bool NextToken(const std::string& delimiters);
const std::string GetToken() const;
void Reset();
protected:
size_t m_offset;
const std::string m_string;
std::string m_token;
std::string m_delimiters;
};
//CPP file
const std::string Tokenizer::DELIMITERS(" \t\n\r");
Tokenizer::Tokenizer(const std::string& s) :
m_string(s),
m_offset(0),
m_delimiters(DELIMITERS) {}
Tokenizer::Tokenizer(const std::string& s, const std::string& delimiters) :
m_string(s),
m_offset(0),
m_delimiters(delimiters) {}
bool Tokenizer::NextToken()
{
return NextToken(m_delimiters);
}
bool Tokenizer::NextToken(const std::string& delimiters)
{
size_t i = m_string.find_first_not_of(delimiters, m_offset);
if (std::string::npos == i)
{
m_offset = m_string.length();
return false;
}
size_t j = m_string.find_first_of(delimiters, i);
if (std::string::npos == j)
{
m_token = m_string.substr(i);
m_offset = m_string.length();
return true;
}
m_token = m_string.substr(i, j - i);
m_offset = j;
return true;
}
例子:
std::vector <std::string> v;
Tokenizer s("split this string", " ");
while (s.NextToken())
{
v.push_back(s.GetToken());
}
Boost::tokenizer是您的好朋友,但是请考虑使用wstring/wchar_t而不是传统的string/char类型,使您的代码在国际化(i18n)问题上具有可移植性。
#include <iostream>
#include <boost/tokenizer.hpp>
#include <string>
using namespace std;
using namespace boost;
typedef tokenizer<char_separator<wchar_t>,
wstring::const_iterator, wstring> Tok;
int main()
{
wstring s;
while (getline(wcin, s)) {
char_separator<wchar_t> sep(L" "); // list of separator characters
Tok tok(s, sep);
for (Tok::iterator beg = tok.begin(); beg != tok.end(); ++beg) {
wcout << *beg << L"\t"; // output (or store in vector)
}
wcout << L"\n";
}
return 0;
}
我贴出了类似问题的答案。 不要白费力气。我使用过许多库,我遇到过的最快、最灵活的库是:c++ String Toolkit Library。
这里有一个如何使用它的例子,我已经张贴在stackoverflow的其他地方。
#include <iostream>
#include <vector>
#include <string>
#include <strtk.hpp>
const char *whitespace = " \t\r\n\f";
const char *whitespace_and_punctuation = " \t\r\n\f;,=";
int main()
{
{ // normal parsing of a string into a vector of strings
std::string s("Somewhere down the road");
std::vector<std::string> result;
if( strtk::parse( s, whitespace, result ) )
{
for(size_t i = 0; i < result.size(); ++i )
std::cout << result[i] << std::endl;
}
}
{ // parsing a string into a vector of floats with other separators
// besides spaces
std::string s("3.0, 3.14; 4.0");
std::vector<float> values;
if( strtk::parse( s, whitespace_and_punctuation, values ) )
{
for(size_t i = 0; i < values.size(); ++i )
std::cout << values[i] << std::endl;
}
}
{ // parsing a string into specific variables
std::string s("angle = 45; radius = 9.9");
std::string w1, w2;
float v1, v2;
if( strtk::parse( s, whitespace_and_punctuation, w1, v1, w2, v2) )
{
std::cout << "word " << w1 << ", value " << v1 << std::endl;
std::cout << "word " << w2 << ", value " << v2 << std::endl;
}
}
return 0;
}
这里有许多过于复杂的建议。试试这个简单的std::string解决方案:
using namespace std;
string someText = ...
string::size_type tokenOff = 0, sepOff = tokenOff;
while (sepOff != string::npos)
{
sepOff = someText.find(' ', sepOff);
string::size_type tokenLen = (sepOff == string::npos) ? sepOff : sepOff++ - tokenOff;
string token = someText.substr(tokenOff, tokenLen);
if (!token.empty())
/* do something with token */;
tokenOff = sepOff;
}
这是一个简单的循环,只对标准库文件进行标记
#include <iostream.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <conio.h>
class word
{
public:
char w[20];
word()
{
for(int j=0;j<=20;j++)
{w[j]='\0';
}
}
};
void main()
{
int i=1,n=0,j=0,k=0,m=1;
char input[100];
word ww[100];
gets(input);
n=strlen(input);
for(i=0;i<=m;i++)
{
if(context[i]!=' ')
{
ww[k].w[j]=context[i];
j++;
}
else
{
k++;
j=0;
m++;
}
}
}