TCS difference between sum of diagonal of 2D matrix

#include<conio.h>
#include<iostream>
#include<stdio.h>
#include<stdlib.h>
using namespace std;
int main()
{
	int p,q,i,j,sum1=0,result,sum2=0;
	cout<<"enter size of array";
	cin>>p;
	int a[p][p];
	for(i=1;i<=p;i++)
	{
		for(j=1;j<=p;j++)
		{
			cin>>a[i][j];
		}
	}
   for(i=1;i<=p;i++)
   {
   	 sum1 = sum1 + a[i][i];
        sum2 = sum2 + a[i][p-i+1];
   }
   result = abs(sum1 - sum2);
    printf("%d",result);
    return 0;
   		
}