需要一些帮助来颠倒单词顺序

Question

Hey guys I've got to take a string of words and re-order them to be backwards in C++. Not spelling them backwards but reverse the sentence essentially. My issue is I have to use cin.get() and I keep getting an error that I cant seem to figure out. The error is "no instance of overloaded function matches the argument list" it says this under the "get" after cin.get Here is my code

#include <iostream>
#include <string>

using namespace std;

int main() {
  string str;
  cin.get(str, 1000);

  int n = str.size();
  int i, j = n;

  for (i = n - 1; i >= 0; i--) {
    if (str[i] == ' ') {
      for (int k = i + 1; k < j; k++) {
        cout << str[k];
      }
      cout << " ";
      j = i;
    }
  }

  for (int k = i + 1; k < j; k++) {
    cout << str[k];
  }

  return 0;
}

Answer 1

Because you included <string> and are using std::string s, we'll use std::getline() .

We are also going to use a std::vector to store the std::string s. Vectors in C++ are arrays that can grow when needed. They can be used just like arrays [and then some], but their dynamic nature makes them a lot more flexible. If for whatever (homework) reason you cannot use vectors, this can still be accomplished with a C-array of std::string s. You'll just have to choose a big enough capacity to handle your possible use-cases. And keep count of how many words you actually have.

My code has a few variations that you can change around by commenting/uncommenting. There are two methods of acquiring words. One has the words being entered individually, and the other has all the words on one line. I also have two ways of reversing the word order; so four total different ways for the code to play out.

#include <algorithm>  // std::reverse()
#include <iostream>
#include <sstream>  // std::istringstream
#include <string>
#include <vector>

std::vector<std::string> get_single_words() {
  std::vector<std::string> words;
  for (std::string tmp; std::getline(std::cin, tmp);) {
    if (tmp != "") {
      words.push_back(tmp);
    } else {
      break;  // Get out of loop on empty string (pressing Enter, only)
    }
  }

  return words;
}

std::vector<std::string> get_line_of_words() {
  std::string line;
  std::getline(std::cin, line);
  std::istringstream sin(line);
  std::vector<std::string> words;

  for (std::string tmp; sin >> tmp;) {
    words.push_back(tmp);
  }

  return words;
}

int main() {
  /*
   * Two methods for obtaining words, uncomment only one at a time
   */
  // auto words = get_single_words();
  auto words = get_line_of_words();

  /*
   * Two methods for printing reversed list, uncomment only one at a time
   */
  // Print in reverse by moving backwards through vector
  //
  for (auto riter = words.rbegin(); riter != words.rend(); ++riter) {
    std::cout << *riter << ' ';
  }
  std::cout << '\n';

  // OR by reversing vector and printing normally
  // (first is better for just printing)
  //
  // std::reverse(words.begin(), words.end());
  // for (const auto& word : words) {
  //   std::cout << word << ' ';
  // }
  // std::cout << '\n';

  return 0;
}