Question

How to convert a 2D array to a 1D array in C++

Answer 1

#include <iostream>

constexpr int SIZE = 3;

void arr2DTo1D(int twoDArray[][SIZE], int oneDArray[], int rows, int cols) {
    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            oneDArray[i * cols + j] = twoDArray[i][j];
        }
    }
}

int main() {
    int twoDArray[SIZE][SIZE] = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
    int oneDArray[SIZE * SIZE];

    arr2DTo1D(twoDArray, oneDArray, SIZE, SIZE);

    for (int i = 0; i < SIZE * SIZE; i++) {
        std::cout << oneDArray[i] << " ";
    }
}


/*
run:

1 2 3 4 5 6 7 8 9 

*/

 

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