how to take infinite input in vector c++ code example

Example 1: initialize 2d vector of ints c++

auto M = 4;	// num of rows
auto N = 3; // num of cols in each row
auto default_value = 1; // default value of all int elements
std::vector<std::vector<int>> matrix(M, std::vector<int>(N, default_value));

Example 2: how to take input in 2d vector in c++

std::vector<vector<int>> d;
//std::vector<int> d;
cout<<"Enter the N number of ship and port:"<<endl;
cin>>in;
cout<<"\Enter preference etc..:\n";
for(i=0; i<in; i++){ 
cout<<"ship"<<i+1<<":"<<' ';
    for(j=0; j<in; j++){
    cin>>temp;
    d[i].push_back(temp); 
    }
}