如何打印出char **向量的内容

Question

SO,

I am looking to print out the contents of a vector; I have tried an iterator for it but that is no good

for(vector<char**>::const_iterator i=myVec.begin();i!=myVec.end();i++) {
   cout<<**i<<endl;
}

this does not work, what I am thinking is I will need two iterators (the above one will be the outer one, and the inner one would be as such:

  for(vector<char*>::const_iterator j=???;j!=??;j++) {....}

but I haven't been able to get it to work.

Thanks.

Answer 1

Seems to work just fine here:

#include <iostream>
#include <vector>

int main()
{
    const char* sentence1[] = {"foo", "bar", "baz"};
    const char* sentence2[] = {"xyzzy", "frob", "plugh"};
    std::vector<const char**> vec = {sentence1, sentence2};

    for (auto i : vec) {
        for (size_t w = 0; w < 3; ++w) {
            std::cout << i[w] << ' ';
        }
    }
    std::cout << '\n';
}

This will print:

foo bar baz xyzzy frob plugh

The above is C++11. If you don't have that, you'll need to change the vector initialization and the for loop:

std::vector<const char**> vec;
vec.push_back(sentence1);
vec.push_back(sentence2);

for (std::vector<const char**>::iterator it = vec.begin();
     it != vec.end(); ++it)
{
    for (size_t w = 0; w < 3; ++w) {
        std::cout << (*it)[w] << ' ';
    }
}

As you can imagine, you'll need to assume the same amount of words for each sentence. If you don't want that, you can create a new data structure that also holds the amount of words per sentence together with the vector of sentences.

Being a masochist is a good exercise, but for practical purposes you should probably switch to vectors so that you can iterate over the words more easily.