Find second to last word in a string C++ - c++

Question

Hi I need to find second to last word in a string. Right now below program is printing the last one.
#include <iostream>
#include <string>
using namespace std;
int main() {
string text{"some line with text"};
// find last space, counting from backwards
int i = text.length() - 2; // last character
while (i != 0 && !isspace(text[i]))
{
--i;
}
string lastword = text.substr(i+1); // +1 to skip leading space
cout << lastword << endl;
return 0;
}
Output: (Printing last word)
text

Answer 1

You can split the string into words and hold the previous word before saving the current word.
#include <iostream>
#include <string>
#include <sstream>
int main() {
std::string text{"some line with text"};
std::stringstream ss(text);
std::string previousword, lastword, newword;
while (ss >> newword) {
previousword = lastword;
lastword = newword;
}
std::cout << previousword << std::endl;
return 0;
}
Also note that using using namespace std; is discouraged.

Answer 2

You don't need any loops. Just add error checking:
int main() {
std::string text{ "some line with text" };
std::size_t pos2 = text.rfind(' ');
std::size_t pos1 = text.rfind(' ', pos2-1);
std::cout << text.substr(pos1+1, pos2-pos1-1) << std::endl;
return 0;
}

Answer 3

Just keep counting spaces until you arrive to the word you want or use a stringstream as MikeCAT proposed.
Here there is a function that finds any last word number without having to copy the entire string in a stringstream:
#include <iostream>
#include <string>
using std::string;
using std::cout;
using std::endl;
string getNLastWord(string text, int n)
{
bool insideAWord = false;
int wordNum = 0;
int wordEnd = -1;
for(int i = text.size() - 1; i > 0; i--)
{
if(text[i] != ' ' && !insideAWord)
{
wordNum++;
insideAWord = true;
}
else if(text[i] == ' ')
{
insideAWord = false;
}
if(wordNum == n)
{
wordEnd = i;
break;
}
}
if(wordEnd == -1)
{
cout << "There are no " << n << " words from right." << endl;
}
else
{
int wordStart;
for(wordStart = wordEnd; wordStart > 0; wordStart--)
{
if(text[wordStart] == ' ')
{
wordStart++;
break;
}
}
return text.substr(wordStart,wordEnd+1-wordStart);
}
return "";
}
int main() {
string text = "some text";
cout << getNLastWord(text,2);
return 0;
}