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For each Loop trick

· One min read
Sarthak Mohanty

taking input using for each​

caution
  • vector must be declared with a size
    vector<int> v(4);

    for (int &el : v)
    {
        cin >> el;
    }
2D vector using for-each loop
    vector<vector<int>> v(k, vector<int>(n));

    for (auto &el : v)
    {
        for (auto &el2 : el)
        {
            cin >> el2;
        }
    }

updating elements using for each​

caution
  • vector must be declared with a size
    vector<int> v(4);


    for (int &el : v)   // using 'Reference' (&el) here
    {
        el = 99;
    }