C program to find maximum number in each column

Below is the program to find maximum number in each column in a given matrix

#include <stdio.h>
int main(){
    int r,c;
    printf("Enter number of rows: ");
    scanf("%d",&r);
    printf("Enter number of columns: ");
    scanf("%d",&c);
    int arr[r][c];
    printf("Enter elements of a matrix\n");
    int i=0,j;
    for(i=0;i<r;i++){
        for(j=0;j<c;j++){
            printf("Enter a%d%d: ",i+1,j+1);
            scanf("%d",&arr[i][j]);
        }
    }
    printf("Elements in the matrix are:\n");
    for(i=0;i<r;i++){
        for(j=0;j<c;j++){
            printf("%d\t\t",arr[i][j]);
        }
    printf("\n\n");
    }
    int matrix[c],max_num=0;
    i=0;
    while(i<c){
        for(j=0;j<r;j++){
            if(arr[j][i]>max_num){
                max_num=arr[j][i];
            }
        }
        matrix[i]=max_num;
        max_num=0;
        i++;
    }
    for(i=0;i<c;i++){
        printf("Largest number in column %d is %d\n",i,matrix[i]);
    }
}

Output:

Enter number of rows: 3
Enter number of columns: 3
Enter elements of a matrix
Enter a11: 5
Enter a12: 2
Enter a13: 7
Enter a21: 8
Enter a22: 1
Enter a23: 9
Enter a31: 4
Enter a32: 7
Enter a33: 3
Elements in the matrix are:
5 2 7

8 1 9

4 7 3

Largest number in column 0 is 8
Largest number in column 1 is 7
Largest number in column 2 is 9