Pointer Arithmetic in C

Hello folks, today we are gonna see how pointer arithmetic actually is and how we can use pointers in our simple program. I’ve implemented a simple array print function that populates a double dimensional array and prints it according to its value.

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

#define ROW 3
#define COLUMN 4


void print_matrix(int array[][COLUMN], int row, int column) {
    for(int i = 0 ; i < row ; i++) {
        for (int j = 0 ; j < column ; j++) {
            printf("%d ",array[i][j]);
        }
        printf("\n");
    }
}

void print_matrix2(int **matrix, int row, int column) {
    for(int i = 0 ; i < row ; i++) {
        for (int j = 0 ; j < column ; j++) {
            printf("%d ",*((*(matrix+i))+j));
        }
        printf("\n");
    }
}

void populate_matrix1(int matrix[][COLUMN], int row , int column) {
    for(int i = 0 ; i < row; i ++){
        for(int j = 0 ; j < column ; j++) {
            matrix[i][j] = i*j + j + 1;
        }
    }
}
void populate_matrix2(int **matrix, int row , int column) {
    for(int i = 0 ; i < row; i ++){
        for(int j = 0 ; j < column ; j++) {
            (*(*(matrix+i)+j)) = i*j + j + 1;
        }
    }
}

int main() {
    printf("Hello World\n");
    int array[ROW][COLUMN];
    int **matrix;
    matrix = (int**)malloc(sizeof(int*)*ROW);
    for(int i = 0 ; i < ROW ; i++) {
        (*(matrix+i)) = malloc(sizeof(int)*COLUMN);
    }

    populate_matrix1(array,ROW,COLUMN);
    populate_matrix2(matrix,ROW, COLUMN);
    print_matrix2(matrix,ROW,COLUMN);
    printf("###\n");
    print_matrix(array,ROW, COLUMN);
    
    return 0;
}

Output:

Hello World
1 2 3 4
1 3 5 7
1 4 7 10
###
1 2 3 4
1 3 5 7
1 4 7 10

This post will be interactive, I’ll respond to every question under this post regarding pointer arithmetic.