Where is my mistake?

Question

You task is to find the column number(index) that have maximum sum of it's elements.

Input
First line N and M (1<=N,M<=100).
Then NxM table is given(all number are integers)

Output
The index of the column with maximum sum of it's elements.

Sample input:
3 4
1 2 3 1
1 5 6 1
1 1 8 1

Sample output:
3

#include <iostream>
using namespace std;

int main() {
int a,b;
cin >>a>>b;
int arr[100][100];

for (int i = 0; i < a; i++) {
for (int j = 0; j < b; j++) {
cin >> arr[i][j];
}
}
int max = arr[0][0];
int x = 0;
for (int i = 0; i < a; i++) {
for (int j = 0; j < b; j++) {
if (max < arr[i][j]) {
max = arr[i][j];
x = i + 1;
}
}
}
cout << x;
return 0;
}

Answer 1

See logics

https://www.google.com/amp/s/www.geeksforgeeks.org/find-row-with-maximum-sum-in-a-matrix/amp/

Answer 2

The below thread, is the third copy on the same problem you described (snippet may vary). Is this a homework or a challenge somewhere?

May I suggest to follow the below thread, instead of posting a similar problem? it'll do a favour in reducing duplicate questions.

https://www.sololearn.com/Discuss/2530887/?ref=app