如何以矩阵形式打印我的 2D 矢量？ C++

Question

I have created a 2D vector that is populated by values in a text file. The values provided will always be N*N so my question is, how can I print out the vector of vectors in a matrix form, ie in a 3x3 grid. My code so far is as follows:

#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

int main()
{
    //Declaration
    string line;
    ifstream myfile("example.txt");
    int n;
    int x;
    myfile >> n;

    //Creation of 2D vector
    vector<vector<int> > grid;
    for(int i = 0; i < n; i++){
        vector<int> temp;
        for(int j = 0; j < n; j++){
            while (myfile >> x){
                temp.push_back(x);
            }
        }
        grid.push_back(temp);
    }

    //Display the elements of the 2D vector

    for (int i=0; i<grid.size(); i++){
        for (int j = 0; j<grid[i].size(); j++){
            cout << "[" << grid[i][j] << "]";
        }
    }
    return 0;
}

As you can see I tried to add cout << "[" << grid[i][j] << "]"; to do this but this only outputs a single line of all the values, any help would be much appreciated!

Answer 1

Put a new line after every loop through i ?

for (int i=0; i<grid.size(); i++) {
    for (int j = 0; j<grid[i].size(); j++) {
        cout << "[" << grid[i][j] << "]";
    }
    // Add a new line after every row
    cout << endl;
}

Answer 2

So I managed to figure it out with the help of @John as he had mentioned the number of vectors I had. I didn't consider that I may have just populated the first vector (j=0) with the values rather than having 3 in j=0,1,2. In the end I used the code:

for (int i=0; i<grid.size(); i++){
    for (int j = 0; j<grid[i].size(); j++){
        cout << "[" << grid[i][j] << "] ";
        if((j+1)%n == 0){
            cout << endl;
        }
    }
}

This displayed it as I had requested but I had the underlying problem as they were all in 1 sub-vector. This was simply fixed by changing the:

while (myfile >> x) { ... }

To:

if (myfile >> x) { ... }

Hope this can help some of you!