我意识到这个问题在过去可能已被多次询问过,但我会继续这样做。
我有一个程序可以从键盘输入中获取一串数字。数字将始终采用“66 33 9”的形式。基本上,每个数字都用空格分隔,用户输入将始终包含不同数量的数字。
我知道如果每个用户输入的字符串中的数字量不变,使用'sscanf'会有效,但对我来说情况并非如此。另外,因为我是C ++的新手,所以我更喜欢处理'字符串'变量而不是字符数组。
答案 0 :(得分:35)
我假设您想要读取整行,并将其解析为输入。所以,先抓住这条线:
std::string input;
std::getline(std::cin, input);
现在把它放在stringstream
:
std::stringstream stream(input);
并解析
while(1) {
int n;
stream >> n;
if(!stream)
break;
std::cout << "Found integer: " << n << "\n";
}
请记住包含
#include <string>
#include <sstream>
答案 1 :(得分:19)
C++ String Toolkit Library (Strtk)针对您的问题提供了以下解决方案:
#include <iostream>
#include <string>
#include <deque>
#include <algorithm>
#include <iterator>
#include "strtk.hpp"
int main()
{
std::string s = "1 23 456 7890";
std::deque<int> int_list;
strtk::parse(s," ",int_list);
std::copy(int_list.begin(),
int_list.end(),
std::ostream_iterator<int>(std::cout,"\t"));
return 0;
}
可以找到更多示例Here
答案 2 :(得分:9)
#include <string>
#include <vector>
#include <iterator>
#include <sstream>
#include <iostream>
int main() {
std::string input;
while ( std::getline( std::cin, input ) )
{
std::vector<int> inputs;
std::istringstream in( input );
std::copy( std::istream_iterator<int>( in ), std::istream_iterator<int>(),
std::back_inserter( inputs ) );
// Log process:
std::cout << "Read " << inputs.size() << " integers from string '"
<< input << "'" << std::endl;
std::cout << "\tvalues: ";
std::copy( inputs.begin(), inputs.end(),
std::ostream_iterator<int>( std::cout, " " ) );
std::cout << std::endl;
}
}
答案 3 :(得分:3)
#include <string>
#include <vector>
#include <sstream>
#include <iostream>
using namespace std;
int ReadNumbers( const string & s, vector <int> & v ) {
istringstream is( s );
int n;
while( is >> n ) {
v.push_back( n );
}
return v.size();
}
int main() {
string s;
vector <int> v;
getline( cin, s );
ReadNumbers( s, v );
for ( int i = 0; i < v.size(); i++ ) {
cout << "number is " << v[i] << endl;
}
}
答案 4 :(得分:1)
Here is如何将字符串拆分为沿空格的字符串。然后你可以逐个处理它们。
答案 5 :(得分:1)
// get string
std::string input_str;
std::getline( std::cin, input_str );
// convert to a stream
std::stringstream in( input_str );
// convert to vector of ints
std::vector<int> ints;
copy( std::istream_iterator<int, char>(in), std::istream_iterator<int, char>(), back_inserter( ints ) );
答案 6 :(得分:1)
无符号值的通用解决方案(处理前缀' - '需要额外的布尔值):
template<typename InIter, typename OutIter>
void ConvertNumbers(InIter begin, InIter end, OutIter out)
{
typename OutIter::value_type accum = 0;
for(; begin != end; ++begin)
{
typename InIter::value_type c = *begin;
if (c==' ') {
*out++ = accum; accum = 0; break;
} else if (c>='0' && c <='9') {
accum *= 10; accum += c-'0';
}
}
*out++ = accum;
// Dealing with the last number is slightly complicated because it
// could be considered wrong for "1 2 " (produces 1 2 0) but that's similar
// to "1 2" which produces 1 0 2. For either case, determine if that worries
// you. If so: Add an extra bool for state, which is set by the first digit,
// reset by space, and tested before doing *out++=accum.
}
答案 7 :(得分:0)
首先尝试strtoken
分隔字符串,然后处理每个字符串。