Question

How to create an array from a 2D array that only includes the non-zero elements in C

Answer 1

#include <stdio.h>
#include <stdlib.h>

#define ROWS 3
#define COLS 4

void collect_non_zero_elements(int rows, int cols, int array[][cols], int *nonZeroList, int *count) {
    *count = 0;

    // Collect non-zero elements
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            if (array[i][j] != 0) {
                nonZeroList[(*count)++] = array[i][j];
            }
        }
    }
}

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

    int nonZeroList[ROWS * COLS] = {0}; // Assuming a maximum of 12 elements
    int count = 0;

    
    collect_non_zero_elements(ROWS, COLS, array, nonZeroList, &count);
    
    for (int i = 0; i < count; i++) {
        printf("%d ", nonZeroList[i]);
    }

    return 0;
}



/*
run:

1 8 2 7 3 9 4 

*/

 

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