在下面给出的示例中，我如何在向量的向量中 push_back？

Question

I am trying to parse a text file. The text file can be different it depends on the user. The text file will be similar like this,

turn 1 12x13 14x14 5x4 1x2 

turn 2 13x13 14x14 5x3 1x3 3x5

turn 3 13x14 14x13 5x2 1x4 1x9 1x12 20x25

turn 4 14x14 14x12 5x1 1x5 12x9

turn 5 14x13 14x12 5x2 

I've created a vector<vector<string>> str to store the text line by line. But I want to store the text like this,

str[0][0]=="12x13", str[0][0]=="14x14" ...
str[1][0]=="13x13", str[1][0]=="14x14" ...
str[2][0]=="13x14", str[1][0]=="14x13" ...
...

I want to store just the numbers separately, and ignore turn 1 , turn 2 etc.. How can I push_back these inputs in str?

Answer 1

You can initialize it like this:

 vector<vector<string> > vec{ { "1", "2", "3" }, 
                          { "4", "5", "6" }, 
                          { "7", "8", "9" } };

or insert into the vector as:

string s;    
for (int i = 0; i < ROW; i++) { 

        vector<string> v1; 

        for (int j = 0; j < COL; j++) { 
            cin>>s;
            v1.push_back(s); 
        } 
        vec.push_back(v1); 
    } 

Answer 2

If you have each line ready, you can push_back using

vector<vector<string>> str;
str.push_back({"12x13", "14x14", "5x4", "1x2"});

Or you can do this:

vector<vector<string>> str;
str.push_back(vector<string>{});
str.at(0).push_back("12x13");