Kiem tra đối xung ma trận

#include <iostream>
using namespace std;
void nhap(int a[][100],int n)
{
int i,j;
for(i=0;i<n;i++)
for(j=0;j<n;j++)
{
cout<<"A["<<i<<" "<<j<<"]=";
cin>>a[j];
}
}
void kiemtra(int a[][100],int n)
{
int kq=0;
int i,j;
for(i=0;i<n;i++)
for(j=0;j<n;j++)
{
if(a[j]==a[j])
kq=1;
else
{kq=0;break;}
}
if(kq==1)
cout<<"Matranx doi xung"<<endl;
else
cout<<"Matranx khong doi xung<<endl";
}
void main()
{
int n;
int a[100][100];
cout<<"\n\nNhap hang=cot\n\n________________________________________\n\n";
cin>>n;
cout<<"\n\nNhap Matranx\n\n_____________________________________\n\n";
nhap(a,n);
cout<<"\n\nKiem tra Matranx\n\n_____________________________________\n\n";
kiemtra(a,n);
}