Replace Question Mark

#include "stdafx.h"
#include<iostream>
using namespace std;

int main()
{
int arr[4][3]={
{8,'?',21},
{35,'?',12},
{32,'?',31},
{4,'?',28}
};

int l,sum=0;
for(int i=0;i < 4;i++)
{

for(int j=0;j < 3;j++)
{
if(j>0)
{
l=arr[i][0];
if(j==2 && arr[i][j-1]==(int)'?')
{
int val=arr[i][j];
while(val!=0)
{
sum=sum+val%10;
val/=10;
}
arr[i][j-1]=l-sum; // m
cout<<arr[i][j-2]<<"\t"<<arr[i][j-1]<<"\t"<<arr[i][j]<<endl;
sum=0;
}

}
}
}
}