Why does my two-dimensional array print out incorrect values?

I'm trying to print the sum of columns 1, 4 and 6. When I input 30 values into the 2d array, only the fist column is has the correct output.

Code:

---

#include <stdio.h>


int main()
{
    int i, j, sum1=0, sum2=0, sum3=0;
    int arr[5][6];


    for(i=0; i < 5; i++){
        for(j=0; j<6; j++){
            printf("Enter a value: ");
            scanf("%d",&arr[i][j]);
            ;
        }
    }


    printf("Elements of 2D array:- \n");
  for(i=0; i<5; i++) {
      for(j=0; j<6; j++) {
        printf("%d ", arr[i][j]);
        if(j==5){
            printf("\n");
        }
      }
  }


//this functions calculate the sum of the 1st column//
    for(i=0; i<1; i++){
        for(j=0; j<6; j++){
          sum1 += arr[j][i];
        }
    printf("Sum of 1st column is: %d\n", sum1);
        sum1=0;
  }




//this functions calculate the sum of the 4th column//
  for(i=0; i<1; i++){
        for(j=3; j<6; j++){
          sum2 = arr[j][i] + sum2;
          }
    printf("Sum of 4th column is: %d\n", sum2);
        sum2=0;
  }


//this functions calculate the sum of the 6th column//
    for(i=0; i<1; i++){
          for(j=5; j<6; j++){
          sum3 = arr[j][i] + sum3;
          }
    printf("Sum of 6th column is: %d\n", sum3);
        sum3=0;
  }


    return 0;
}

---

Code:

---

#include <stdio.h>
 
#define ROWS 5
#define COLS 6
 
int main()
{
    int arr[ROWS][COLS];
    for (int r = 0; r < ROWS; r++)
        for (int c = 0; c < COLS; c++) {
            printf("Enter a value: ");
            scanf("%d", &arr[r][c]);
        }
 
    printf("Elements of 2D array:-\n");
    for (int r = 0; r < ROWS; r++) {
        for (int c = 0; c < COLS; c++)
            printf("%3d ", arr[r][c]);
        printf("\n");
    }
 
    int sum = 0;
    for (int r = 0; r < ROWS; r++)
        sum += arr[r][0];
    printf("Sum of 1st column is: %d\n", sum);
 
    sum = 0;
    for (int r = 0; r < ROWS; r++)
        sum += arr[r][3];
    printf("Sum of 4th column is: %d\n", sum);
 
    sum = 0;
    for (int r = 0; r < ROWS; r++)
        sum += arr[r][5];
    printf("Sum of 6th column is: %d\n", sum);
 
    return 0;
}

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Thank you bro, I appreciate your help!
It finally work!