为什么 std::reverse() 不反转字符串？

Question

I am trying to reverse an input sentence word by word. For example :

Input : This is a sentence

The output should be :

Output : sentence a is This

So I am using strings in the following code :

#include <iostream>
#include <string>
#include <cstring>
#include <algorithm>

int main()
{
    

        std::string sentence("This is a sentence"), rev_sentence;
        char *words = new char[20];
        
        std::cout <<"This is the sentence : "<< sentence << std::endl;
        
        words = strtok(&sentence[0], " "); //Tokenizing
        while (words != NULL)
        {
            rev_sentence.append(words);
            rev_sentence += ' ';
            words = strtok(NULL, " ");
        }
        rev_sentence.pop_back(); //Removing the last blankspace
        
        std::cout <<"This is before final reverse : " << rev_sentence << std::endl;
        
        std::reverse(rev_sentence.begin(), rev_sentence.end()); //reverse()
        std::cout << rev_sentence << std::endl;
    return 0;
}

The output is fine before std::reverse() but it does not print the final output once I call it. Can anyone specify what I am doing wrong?

Answer 1

You are trying to reverse the characters of a string, as element of std::string rev_sentence are characters.

Use a container with string elements, like std::vector<std::string> as the source for reverse.