Question

vector <string> oneWordPhrase;
vector <string> twoWordPhrase;
vector <string> threeWordPhrase;    

string str="hello my is bob oh hey jay oh";

vector<string>::iterator it1;
vector<string>::iterator it2;

我把句子用str语言分成单个单词并将它们存储到名为oneWordPhrase的向量中。因此，矢量的大小为7

for(it1=oneWordPhrase.begin(); it1!=oneWordPhrase.end(); it1++)
{
    if(it1+1 == oneWordPhrase.end())
        break;  /* if we reach the last element of the vector
                     get out of loop because we reached the end */
    twoWordPhrase.push_back(*it1 + ' ' + *(it1+1));
}//gets each 2 consecutive words in the sentence

cout<<"two word---------------\n";
for(int i=0; i<twoWordPhrase.size(); i++)
    cout<<twoWordPhrase[i]<<endl;

这会产生正确的输出：

你好我的

我的

是bob

鲍勃哦

哦，嘿嘿

嘿杰伊

jay oh

for(int i=0; i<twoWordPhrase.size()-1; i++)
{   
    it1=twoWordPhrase.begin()+i;
    it2=oneWordPhrase.begin()+i+2;
    if(it1==twoWordPhrase.end()-1)
        break; //signal break but doesnt work
    threeWordPhrase.push_back(*it1 + ' ' + *it2);
}
cout<<"three words-----------\n";
for(int i=0; i<threeWordPhrase; i++)
    cout<<threeWordPhrase[i]<<endl;

这会产生正确的输出，但最后有两行空格

你好我的

我的是鲍勃

是bob哦

鲍勃哦嘿

哦，嘿，杰伊

//空白

我还尝试在for循环中使用迭代器来发出中断信号，但它没有用。为什么要打印两行额外的空格？

Answer 1

要回答原始问题，发布的代码是正确的。正如JosephMansfield所怀疑的那样，显示代码（未发布）中出现了错误，如demonstrated here。

关于风格和最佳实践的评论，我认为以下是更惯用的C ++：

#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include <iterator>

using namespace std;
typedef vector<string> strings;

int main() {
    string s = "one two three four five";

    /* stringstream is a stream just like std::cout
       but reads/writes from/to a string
       instead of the standard input/output */
    stringstream ss(s);

    /* std::vector has a 2 argument constructor
       which fills the vector with all elements between two iterators
       istream_iterator iterates throuw the stream as if
       using operator>> so it reads word by word */
    strings words = 
        strings(istream_iterator<string>(ss), istream_iterator<string>());

    strings threeWords;
    for(size_t i = 0; i < words.size()-2; ++i)
        threeWords.push_back(words[i] + ' ' + words[i+1] + ' ' + words[i+2]);

    for(size_t i = 0; i < threeWords.size(); ++i)
        cout << i << ": " << threeWords[i] << endl;

    return 0;
}

单词拆分代码的灵感来自this post

打印短语c ++中的错误

1 个答案: