Question

How to allocate and deallocate 2D array dynamically in C

Answer 1

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

int **allocate2DArray(int row, int col)
{
    int **pp = (int **) malloc(sizeof(int *)*row);
    
    for(int i = 0; i < row; i++)
        pp[i] = (int *) malloc(sizeof(int)*col);

    return pp;
}

void delete2DArray(int **pp, int row)
{
    for(int i = 0; i < row; i++)
        free(pp[i]);
    
    free(pp);
}

void init(int **pp, int row, int col)
{
    for (int i = 0; i < row; i++)
        for (int j = 0; j < col; j++)
            pp[i][j] = i * j + 1;
}

void print(int **pp, int row, int col)
{
    for (int i = 0; i < row; i++)
    {
        for (int j = 0; j < col; j++)
            printf("%3d", pp[i][j]);
        
        printf("\n");
    }
}


int main()
{
    int row = 3, col = 4;
    int **arr2d = allocate2DArray(row, col);

    init(arr2d, row, col);

    print(arr2d, row, col);

    delete2DArray(arr2d, row);

    return 0;
}


/*
run:

  1  1  1  1
  1  2  3  4
  1  3  5  7

 */

 

70+ SQL courses for beginners and professionals