Question

How to map a 2D array element to a 1D array in C

Answer 1

#include <stdio.h>

#define ROWS 3
#define COLS 4
#define SIZE ROWS * COLS

int set2DElementTo1D(int arr[], int row, int col, int value) {
    arr[row * COLS + col] = value;
}

int main() {
    int arr2d[ROWS][COLS] = { 
        { 5, 6, 1, 4 }, 
        { 3, 0, 8, 2 },
        { 9, 2, 7, 1 } 
    };

    int arr[SIZE] = {0};
    set2DElementTo1D(arr, 1, 2, arr2d[1][2]);

    for (int i = 0; i < SIZE; i++) {
        printf("%d ", arr[i]);
    }

    return 0;
}

 
/*
run:
 
0 0 0 0 0 0 8 0 0 0 0 0 
 
*/

 

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