without extra multiple space between two words.

reverse_words_in_string.cpp

#include <iostream>
#include <string>
#include <stack>
#include <tuple>
using namespace std;
string reverseWords(string sentence) {
    stack<string> words_stack;
    string word = "";
    for(int i=0; i<sentence.size(); ++i){
        if(sentence[i] == ' ' && word != ""){
            // cout<<word<<endl;
            words_stack.push(word);
            word = "";
        }
        if(sentence[i] != ' ')
            word += sentence[i];
    }
    if(word != "") words_stack.push(word);
    string new_sentence = "";
    while(!words_stack.empty()){
        new_sentence += ' ';
        new_sentence += words_stack.top();
        words_stack.pop();
    }
    new_sentence.erase(0,1);// remove first extra space
    return new_sentence;
}
int main(){
    string sentence = "queen loves king";
    cout<< reverseWords(sentence);
    return 0;
}