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  1. #include <iostream>
  2. #include <vector>
  3. using namespace std;
  4. vector<vector<int> > vec;
  5.  
  6. int main() {
  7.   vec.resize(5);  // Only the first dimension has the fixed size
  8.   vec.at(2).push_back(2);  // If I do vec[2].push_back(2), it will work
  9.   vec.at(1).push_back(34);
  10.   for (int i = 0; i < 5; ++i) {
  11.     cout << vec[i].size() << endl;  // output: 0
  12.     for (int j = 0; j < vec[i].size(); ++j) {
  13.        cout << vec[i][j] << endl;
  14.     }
  15.   }
  16. }
Success #stdin #stdout 0s 3460KB
comments (?)
stdin 
Standard input is empty
stdout 
0
1
34
1
2
0
0
https://ideone.com/jmIWcW
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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