I am learning C++ using recommended C++ books. In particular, i read about std::istringstream
and saw the following example:
std::string s("some string");
std::istringstream ss(s);
std::string word;
while(ss >> word)
{
std::cout<<word <<" ";
}
Actual Output
some string
Desired Output
string some
My question is that how can we create the above std::istringstream
object ss
using the reversed string(that contains the word in the reverse order as shown in the desired output)? I looked at std::istringstream's constructors but couldn't find one that takes iterators so that i can pass str.back()
and str.begin()
instead of passing a std::string
.
You can pass iterators to the istringstream
constructor indirectly if you use a temporary string:
#include <sstream>
#include <iostream>
int main()
{
std::string s{"Hello World\n"};
std::istringstream ss({s.rbegin(),s.rend()});
std::string word;
while(ss >> word)
{
std::cout<<word <<" ";
}
}
dlroW olleH
Though thats reversing the string, not words. If you want to print words in reverse order a istringstream
alone does not help much. You can use some container to store the extracted words and then print them in reverse:
#include <sstream>
#include <iostream>
#include <vector>
int main()
{
std::string s{"Hello World\n"};
std::istringstream ss(s);
std::string word;
std::vector<std::string> words;
while(ss >> word)
{
words.push_back(word);
}
for (auto it = words.rbegin(); it != words.rend(); ++it) std::cout << *it << " ";
}
World Hello