C++中的Anagram finder程序

我需要编写一个程序来查找单词的变位符号。当程序启动时，它要求用户将单词输入到"词典"中，稍后将在该词典中搜索用户将再次输入的单词的变位符号。

我把字典中的所有单词都存储在一个名为oldDict的向量中。然后，每个单词中的字符按字母顺序排列，并将新的字符排序的单词存储在一个称为newDict的向量中，以保留oldDict中的原始单词。

然后，用户输入一个单词，该单词的变位词必须在字典中找到。单词一输入，我就再次尝试按字母顺序对单词的字符进行排序，以便将其与newDict中的每个元素进行比较，并以这种方式找到变位符。

以下是我的代码：

ifndef ANAGRAM_H
#define ANAGRAM_H
#include <iostream>
#include <vector>
#include <string>
using namespace std;
vector <string> oldDict;
vector <string> newDict;
int dictSize = 0;
void readDict(void){    // Allows the user to input all the words they would like to     have in the anagram dictionary.
    cout<< "Please enter the number of dictionary entries you wish to createn";
    cin >> dictSize;
    string word = "";
    cout << "Please enter the dictionary entries, 1 by 1, pushing <enter> after each entry.n";
    for(int i = 0; i <dictSize; i++){
        cin >> word;
        oldDict.push_back(word);
    }
    newDict = oldDict;
}   
void sortChars(void){   //sorts the letters in each word of the 'dictionary' so that the     letters are in alphabetical order.
    for(int i = 0; i < dictSize; i++){
        std::sort(newDict[i].begin(), newDict[i].end());    
    }
}
void getWords(void){
    int num = 0;
    cout << "Please enter the number of words for which you would like to find anagrams     of:n";
    cin >> num;
    string word = "";
    for(int i = 0; i < num; i ++){
        cout << "Please enter a word:n";
        cin>>word;
        std::sort(word.begin(), word.end());    
        for(int i = 0; i < dictSize; i++){
            string word2 = newDict[i];
            bool isAn = isAnagram(word, word2);
            if(isAn == true){
                cout << oldDict[i];
            } else{
            }
        }
    }
}
bool isAnagram(string word1, string word2){
    if(word1.compare(word2) ==0){
        return true;
    } else {
        return false;   
    }
}
void menu(void){
    readDict();
    sortChars();
    getWords();
}
#endif

该过程从代码底部的order()函数开始。

当试图编译代码时，我收到以下错误：

In file included from main.cpp:3:0:
./anagram.h: In function ‘void sortChars()’:
./anagram.h:25:3: error: ‘sort’ is not a member of ‘std’
   std::sort(newDict[i].begin(), newDict[i].end()); 
   ^
./anagram.h: In function ‘void getWords()’:
./anagram.h:37:4: error: ‘sort’ is not a member of ‘std’
    std::sort(word.begin(), word.end()); 
    ^
./anagram.h:40:38: error: ‘isAnagram’ was not declared in this scope
     bool isAn = isAnagram(word, word2);

有人能帮我解决那些错误吗？我真的不明白"isAnagram"给出的是错误，如果有人能解释一下"std:："是什么，为什么这两行代码会产生错误？

非常感谢