处理包含多个向量的数组中的值

Question

So basically I have created an array containing two vectors, and I want to be able to change/output values. I have read that the following syntax should work, but when I run the program, it just keeps filling up the memory without printing anything.

#include <iostream>
#include <array>
#include <vector>

int main() {
    std::array<std::vector<float>, 2> endPieceV;

    for (int i = 0; i < 20; i+2) {
        endPieceV[0].push_back(i);
        endPieceV[1].push_back(i*i+2);
    }

    std::cout << "Vector 1:" << std::endl;
    for (int i = 0; i < endPieceV[0].size(); i++) {
        std::cout << endPieceV[0][i] << " ";
    }

    std::cout << std::endl;
    std::cout << std::endl;

    std::cout << "Vector 2:" << std::endl;
    for (int i = 0; i < endPieceV[0].size(); i++) {
        std::cout << endPieceV[1][i] << " ";
    }
system("pause");
return 0;
}

I don't understand why it doesn't start printing, but just keeps loading?

Answer 1

This loop counter is is incorrect:

 for (int i = 0; i < 20; i+2)

You're not incrementing i in this loop.

Another potential error is that you're using the wrong vector as the loop counter:

 for (int i = 0; i < endPieceV[0].size(); i++) {
                            // ^ Wrong, should be 1
        std::cout << endPieceV[1][i] << " ";

Even though you mentioned that the vectors are the same size, this is really not the way to write a loop like this.

Answer 2

You are not incrementing i in first loop

for (int i = 0; i < 20; i+2) {
        endPieceV[0].push_back(i);
        endPieceV[1].push_back(i*i+2);
    }

Notice i+2 should be i+=2