Answers for "ways of initializing vector in c++"

initialize vector of vector c++

#include <iostream>
#include <vector>
 
#define M 3
#define N 4
 
int main()
{
  // specify default value to fill the vector elements
  int default_value = 1;
  // first initialize a vector of ints with given default value
  std::vector<int> v(N, default_value);
  // Use above vector to initialize the two-dimensional vector
  std::vector<std::vector<int>> matrix(M, v);
  
  return 0;
}

c++ vector initialization

vector<int> a;                                       // empty vector of ints
vector<int> b (5, 10);                                // five ints with value 10
vector<int> c (b.begin(),b.end());                     // iterating through second
vector<int> d (c);                                   // copy of c