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  • Initialize a vector in C++ (5 different ways)

    https://www.geeksforgeeks.org/initialize-a-vector-in-cpp-different-ways/

    Following are different ways to create and initialize a vector in C++ STL

    Initializing by one by one pushing values :

    // CPP program to create an empty vector
    // and one by one push values.
    #include <bits/stdc++.h>
    using namespace std;
     
    int main()
    {
        // Create an empty vector
        vector<int> vect;
        
        vect.push_back(10);
        vect.push_back(20);
        vect.push_back(30);
     
        for (int x : vect)
            cout << x << " ";
     
        return 0;
    }
    Output:
    10 20 30
    

    Specifying size and initializing all values :

    // CPP program to create an empty vector
    // and one by one push values.
    #include <bits/stdc++.h>
    using namespace std;
     
    int main()
    {
        int n = 3;
     
        // Create a vector of size n with
        // all values as 10.
        vector<int> vect(n, 10);
     
        for (int x : vect)
            cout << x << " ";
     
        return 0;
    }

    Output:

    10 10 10
    

    Initializing like arrays :

    // CPP program to initialize a vector like
    // array.
    #include <bits/stdc++.h>
    using namespace std;
     
    int main()
    {
        vector<int> vect{ 10, 20, 30 };
     
        for (int x : vect)
            cout << x << " ";
     
        return 0;
    }
    Output:
    10 20 30
    

    Initializing from array :

    // CPP program to initialize a vector from
    // array.
    #include <bits/stdc++.h>
    using namespace std;
     
    int main()
    {
        int arr[] = { 10, 20, 30 };
        int n = sizeof(arr) / sizeof(arr[0]);
     
        vector<int> vect(arr, arr + n);
     
        for (int x : vect)
            cout << x << " ";
     
        return 0;
    }
    Output:
    10 20 30
    

    Initializing from another vector :

    // CPP program to initialize a vector from
    // another vector.
    #include <bits/stdc++.h>
    using namespace std;
     
    int main()
    {
        vector<int> vect1{ 10, 20, 30 };
     
        vector<int> vect2(vect1.begin(), vect.end());
     
        for (int x : vect2)
            cout << x << " ";
     
        return 0;
    }
    Output:
    10 20 30
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  • 原文地址:https://www.cnblogs.com/time-is-life/p/9510483.html
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