【C++】打印二维vector＜vector＜int＞＞（多种方法）

StackOverFlow

1. range-based loop

// range-based loop
void PrintVecofVec1(vector>& res) {
  for (auto& rowV : res) {
    for (auto& el : rowV) {
      cout << el << " ";
    }
    cout << "; ";
  }
  cout << endl;
}

2. for遍历

void PrintVecofVec2(vector>& A) {
 for (int i = 0; i < A.size(); i++) {       // 行数
   for (int j = 0; j < A[i].size(); j++) {  // A[i].size() 第i行的列数
     cout << A[i][j] << " ";
   }
   cout << endl;
 }
}

3. Iterator

// Iterator
void PrintVecofVec3(vector>& A) {
  for (vector>::iterator i = A.begin(); i != A.end(); i++) {
    for (vector::iterator j = i->begin(); j != i->end(); j++) {
      cout << *j << " ";
    }
    cout << endl;
  }
}

4. lambda表达式

// a generic lambda to serialize vector
void PrintVecofVec4(vector>& A) {
  auto print_vector = [](const auto& v) {
    for_each(v.begin(), v.end(),
             [](auto const& it) { std::cout << it << std::endl; });
  };
  for_each(A.begin(), A.end(), print_vector);
}

void PrintVecofVec5(vector>& A) {
  std::for_each(A.begin(), A.end(), [](const auto& v) {
    std::for_each(v.begin(), v.end(),
                  [](auto const& it) { std::cout << it << std::endl; });
  });
}